Definition of ad lib in US English:

ad lib

adverb & adjective

  • 1Spoken or performed without previous preparation.

    as adverb ‘I spoke ad lib’
    as adjective ‘an ad-lib commentary’
    • ‘He is a messy, carefree drunk, prone to loud outbursts, spontaneous characterisations and ad-lib renditions of whatever comes to his mind.’
    • ‘I am hoping that this will go well enough and that the audience will be understanding enough to allow me then just to chat ad-lib about the other stuff that has happened so far.’
    • ‘Neither guy is robotic in the goal, nor is either above throwing in the odd ad-lib move.’
    • ‘Some blame the prevalence of ad-lib comedy and shows.’
    • ‘This nomadic improvisation troupe takes its ad-lib comedy to movie theatres and bars.’
    • ‘If one goes by the findings of behavioural studies, one would think twice before assigning baby-sitting functions for the telly or hold back from going ga ga over the toddler who lisps ad-lib.’
    • ‘The newsreader said ‘We'll be back for more of what appears to be an ad-lib speech from Mark Oaten’.’
    • ‘It's been said that master comedian Bob Hope never delivered an ad-lib line and Kormos says it's rare to find a comic who can truly improvise.’
    • ‘His immediate response showed showed his flinty ad-lib ability.’
    • ‘Kidder follows up with an ad-lib joke: ‘I'll have what she's having.’’
    • ‘Given the band started out from boozy ad-lib jam sessions, this has all been rather unexpected.’
    • ‘Yet, thankfully, for all the hype, it's still a low-tech performance with poor dancing, ad-lib singing and plenty of knee-sliding across the stage.’
    • ‘Some remember the ad-lib commentary you could provide just with a house mike during a practice.’
    • ‘Jackie's mad ad-lib skills immediately earned him a spot at Manhattan's swanky Club 18.’
    • ‘Even veteran quarterbacks make a mess of these ad-lib moments.’
    • ‘For a medium that thrives on ad-lib banter, trying to find appropriate words when there are none can easily sound banal.’
    • ‘My script was dumped and Bogarde went into freeform ad-lib mode.’
    • ‘She has the natural voice, the crazy ad-lib skills, and an ability to project wisdom that is well beyond her years.’
    • ‘He's back with another improvisation show that combines ad-lib humor with animation.’
    • ‘And I'm not just referring to his series of ridiculous, ad-lib whoppers to the grand jury.’
    impromptu, extempore, without preparation, without rehearsal, extemporaneously, spontaneously, offhand
    impromptu, extempore, extemporaneous, extemporary, improvised, improvisational, improvisatory, improvisatorial, unprepared, unarranged, unplanned, unrehearsed, unscripted, unpremeditated, spontaneous, on-the-spot
    View synonyms
    1. 1.1Music (especially as a direction) with free rhythm and expression.
      • ‘We've been having some nice ad-lib musical jam sessions, thanks to numerous musicians and the international groups around us.’
      • ‘The scoring for the original version of this work is flute and piccolo in D flat, 2 clarinets in E flat (2nd ad lib).’
      • ‘Parts are also included in the set for E flat alto clarinet, B flat contrabass clarinet, and two flugelhorns, all of which are ad lib.’
  • 2As much and as often as desired.

    as adverb ‘the price includes meals and drinks ad lib’
    as adjective ‘the pigs are fed on an ad-lib basis’
    • ‘It is vital that animals are built up on ad-lib meals gradually and that feed is kept in front of them at all times and that they have access to some roughage in the form of straw or silage.’
    • ‘If good quality silage is fed ad-lib to dry cows, energy intakes will exceed requirements which can result in over fat cows at calving with its associated problems.’
    • ‘For young stock and replacement heifers, Keenan have developed a simple feeding system based on ad-lib straw fed with a 21% crude protein balancer.’
    • ‘A simple ration based on ad-lib straw with a protein balancer can be fed to young stock and replacement heifers and this will help preserve grazing.’
    • ‘Animals with more time available for finishing have the option of meals at a lower level plus silage or silage only with ad lib meals.’


  • no object Speak or perform in public without previously preparing one's words.

    ‘Charles had to ad-lib because he'd forgotten his script’
    • ‘I did some ad-libbed material of a similar bent at the gig I did in Brighton last night.’
    • ‘We did 11 comedy albums, and I think 10 were live, and they were all ad-libbed.’
    • ‘He was confident, quick, very good at ad-libbing and feeding off the audience.’
    • ‘After taking the oath of office, George Washington ad-libbed the final words, ‘So help me God.’’
    • ‘Apparently the mental script she was following didn't allow for ad-libbing, for she continued as if he hadn't interrupted.’
    • ‘At one point, they ad-libbed a scene based on their own friendship.’
    • ‘He didn't look like he was being formally interviewed - he looked more like he was inadvisedly ad-libbing at large with an apparently friendly journalist, while the camera just happened to be rolling.’
    • ‘Díaz, who was trying to woo a girl, ad-libbed his own lyrics, which he'd sing to introduce his radio show in the 1940s.’
    • ‘He was doing more ad-libbing and improvisation than me.’
    • ‘Although his drum version of Bring Me To Life was slightly different and it was obvious he was ad-libbing most of it, he managed to stumble his way though.’
    • ‘As a result, the castmembers themselves seem to have ad-libbed most of the week, based on what I imagine was a rough sketch of a few plot points.’
    • ‘I thought his hilarious banter was all ad-libbed.’
    • ‘Howie didn't have an act but he got up there, almost on a dare, and ad-libbed what turned out to be the funniest set of the evening.’
    • ‘This gives him ample time to indulge in ad-libbing, a pastime of which he seems inordinately fond.’
    • ‘Midway, Topher started ad-libbing along on his guitar.’
    • ‘As Bilko, Silvers was never less than sensational, delivering his lines with speed and guile and marvellously ad-libbing when the situation required it.’
    • ‘They allowed me to experiment, they allowed me to take risks, which meant I ad-libbed freely and largely amusingly.’
    • ‘Our star couldn't remember his lines so he ad-libbed all the way through the show.’
    • ‘He is forever quoting the ‘Good Book’, comically ad-libbing when the lines don't suit his purpose.’
    • ‘He was cold, he was bad at ad-libbing and he was very bad at setting up the panelists to be funny.’
    improvise, extemporize, speak impromptu, make it up as one goes along, think on one's feet, take it as it comes
    View synonyms


  • A remark or speech made without previous preparation.

    ‘he came up with an apt ad lib’
    • ‘The propensity for ad-libs lends a natural feel to the dialogue that suits the actor and character, and this is probably the strength of the film.’
    • ‘He started out with very strong ideas about how he wanted the narrative to run and then prepared his actors, encouraging ad-libs and improvisation throughout.’
    • ‘I can recount most of his inspired scripts from memory - with plenty of space for the cast's own contributions and ad-libs.’
    • ‘On the set, Sanders was the perfect self-effacing host, happy to play straightman to his guests or to enliven a dull show with pertinent ad-libs and stupid sketches.’
    • ‘His songs came off best when he would embellish them with ad-libs and stories.’
    • ‘With a stage presence as big as her amazing costumes, her ad-libs and one-liners had the audience in raptures.’
    • ‘The lead vocal is perfect: sung in a dispassionate English accent, devoid of vibrato or ad-libs, everything enunciated as precisely as suburban etiquette would demand.’
    • ‘It's odd comparing which bits of material are standard and which were the ad-libs.’
    • ‘Owen Wilson has a smarmy-cool, utterly natural screen persona of smiles, cheeky ad-libs and ironically understated wisecracks.’
    • ‘The reason there have not been more mess-ups is because of his rule against ad-libs.’
    • ‘The best bits, apart from a few genuinely funny ad-libs, are when the actors seem to break character and reveal things about their own real lives.’
    • ‘The two of them wrote the show from scratch, ensured they got all the best lines and threw in deft ad-libs as required.’
    • ‘Geoff delivers a monologue about divorce with ad-libs to the audience - this is real talent.’
    • ‘But in the final cut, all my ad-libs were in, so we know who won that battle.’
    • ‘We always chatted with the audience before shows and wanted to create something with more ad-libs, auctions, tickets and prizes and thought that was a good idea for an informal show.’
    • ‘Alas it is inevitable if I am going to do edgier stuff and also if I am going to keep the shows looser with more ad-libs and so on.’
    • ‘He makes a game attempt to liven up the dreary proceedings with some clever dialogue and ad-libs.’
    • ‘But of course there are also people who actually expect ‘something’ other than silly comedy and ad-libs from these films, so some really negative reviews too.’
    • ‘He had them rolling in the aisles at his hilarious asides and unscripted ad-libs.’
    • ‘The gravely, growling voice is shot to bits, the performances are hokey, the ad-libs too frequent, and the constant crowd noises irritating.’


Early 19th century (as an adverb): abbreviation of ad libitum.


ad lib

/ˌad ˈlib//ˌæd ˈlɪb/