Definition of ad lib in English:

ad lib


  • Speak or perform in public without previously preparing one's words.

    ‘Charles had to ad lib because he'd forgotten his script’
    [with object] ‘she ad libbed half the speech’
    • ‘He is forever quoting the ‘Good Book’, comically ad-libbing when the lines don't suit his purpose.’
    • ‘Our star couldn't remember his lines so he ad-libbed all the way through the show.’
    • ‘He was confident, quick, very good at ad-libbing and feeding off the audience.’
    • ‘This gives him ample time to indulge in ad-libbing, a pastime of which he seems inordinately fond.’
    • ‘They allowed me to experiment, they allowed me to take risks, which meant I ad-libbed freely and largely amusingly.’
    • ‘After taking the oath of office, George Washington ad-libbed the final words, ‘So help me God.’’
    • ‘He was doing more ad-libbing and improvisation than me.’
    • ‘He was cold, he was bad at ad-libbing and he was very bad at setting up the panelists to be funny.’
    • ‘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.’
    • ‘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.’
    • ‘At one point, they ad-libbed a scene based on their own friendship.’
    • ‘I did some ad-libbed material of a similar bent at the gig I did in Brighton last night.’
    • ‘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.’
    • ‘We did 11 comedy albums, and I think 10 were live, and they were all ad-libbed.’
    • ‘I thought his hilarious banter was all ad-libbed.’
    • ‘Apparently the mental script she was following didn't allow for ad-libbing, for she continued as if he hadn't interrupted.’
    • ‘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.’
    • ‘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.’
    • ‘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.’
    improvise, extemporize, speak impromptu, make it up as one goes along, think on one's feet, take it as it comes
    speak off the cuff, speak off the top of one's head, play it by ear, busk it, wing it
    View synonyms


  • An ad lib remark or speech.

    ‘he came up with an apt ad lib’
    • ‘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.’
    • ‘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.’
    • ‘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.’
    • ‘With a stage presence as big as her amazing costumes, her ad-libs and one-liners had the audience in raptures.’
    • ‘The two of them wrote the show from scratch, ensured they got all the best lines and threw in deft ad-libs as required.’
    • ‘It's odd comparing which bits of material are standard and which were the 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.’
    • ‘Owen Wilson has a smarmy-cool, utterly natural screen persona of smiles, cheeky ad-libs and ironically understated wisecracks.’
    • ‘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.’
    • ‘But in the final cut, all my ad-libs were in, so we know who won that battle.’
    • ‘I can recount most of his inspired scripts from memory - with plenty of space for the cast's own contributions and ad-libs.’
    • ‘He had them rolling in the aisles at his hilarious asides and unscripted ad-libs.’
    • ‘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.’
    • ‘His songs came off best when he would embellish them with ad-libs and stories.’
    • ‘The reason there have not been more mess-ups is because of his rule against 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.’
    • ‘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.’
    • ‘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.’
    • ‘Geoff delivers a monologue about divorce with ad-libs to the audience - this is real talent.’

adjective & adverb

  • 1Spoken or performed without previous preparation.

    ‘an ad lib commentary’
    [as adverb] ‘speaking ad lib’
    impromptu, extempore, without preparation, without rehearsal, extemporaneously, spontaneously, offhand
    ad libitum
    off the cuff, off the top of one's head, on the spur of the moment, just like that, at the drop of a hat
    impromptu, extempore, extemporaneous, extemporary, improvised, improvisational, improvisatory, improvisatorial, unprepared, unarranged, unplanned, unrehearsed, unscripted, unpremeditated, spontaneous, on-the-spot
    off-the-cuff, spur-of-the-moment
    View synonyms
  • 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 system’
  • 3Music
    (in directions) in an improvised manner with freedom to vary tempo and instrumentation.


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


ad lib

/ˌad ˈlib/