Definition of unless in US English:



  • Except if (used to introduce the case in which a statement being made is not true or valid)

    ‘unless you have a photographic memory, repetition is vital’
    ‘manuscripts cannot be returned unless accompanied by a self-addressed envelope’
    • ‘This was a woman who was never in a good mood unless others around her were in a bad mood.’
    • ‘Now how would we know that unless we actually had that dialogue which you commend?’
    • ‘They know that the money would not have been repaid unless its misuse had been made public.’
    • ‘If you haven't got a hat please buy one when you get their unless you want a bad case of sunstroke!’
    • ‘How will I ever know they exist unless I make a special effort to come to your site to check?’
    • ‘The couple look set to split up unless Rodney and Lesley can make them come to their senses.’
    • ‘The first is that there is no chance of them getting into power unless there is a hung parliament.’
    • ‘Next year I will buy my ticket but unless there is a smoking ban I will not be attending.’
    • ‘Everyone should object to every building plan unless it is by the people for the people.’
    • ‘The tags remain active after they have left the store, unless they are switched off.’
    • ‘Gaiman brings it off with a skill that you wouldn't notice unless you were looking for it.’
    • ‘The rest of this post won't make much sense unless you read at least the first poem.’
    • ‘Now the project is destined to fail unless more women can be encouraged to take part.’
    • ‘I'll try not to change point of view in the middle of a scene, unless I need to and it works.’
    • ‘It was now to be the sole means of pursuing a claim, unless you're extremely wealthy.’
    • ‘We don't screen people unless they come from a high risk area such as nursing homes.’
    • ‘She does not read articles about her, unless they are sent to her by her publishers.’
    • ‘The priceless group of wartime ships face the chop unless a new home can be found for them.’
    • ‘We will be counting the loss of that census miscount for years unless the cash is refunded.’
    • ‘Our costs are running ahead of income and unless we take drastic action, we will fail.’


Late Middle English: from on or in (assimilated through lack of stress to un-) + less.