Meaning of LEAST in English
[adverb] [not gradable], determiner, [pronoun] - less than anything or anyone else, the smallest amount or numberThis group is the least likely of the four to win.Disaster struck when we least expected it.It was the answer she least wanted to hear.I like the blue one a little, the red one less, and the green one least of all.He's the relative I like (the) least.Which car costs (the) least?No one believed her, least of all (= especially not) the police.They refused to admit her, not least because (= there were several reasons but this was an important one) she hadn't got her membership card with her.At (the very) least means not less than or shows the lowest amount possible.It will cost at least $100.It will be £200 at the very least. At least is also used to reduce the effect of a statement.I've met the President - at least, he shook my hand once. See also leastways.At least is also used to emphasize that something is good in a bad situation.The letter was very short, but at least she did write to me.It is/was the least I can/could do is a polite answer to someone who thanks you."Thanks for offering to deliver the parcel." "It's the least I can do."Not in the least is used to express strong feeling in negative sentences and means not in any way.I don't like travelling in the least."Are you satisfied with it?" "Not in the least."Not the least is used for emphasis with nouns.I haven't the least idea (= I do not know) who he was.She hasn't the least interest (= She has no interest) in the project.To say the least is used to show that you could have said something stronger.He wasn't happy with the decision, to say the least!(saying) 'Least said soonest mended' means a bad situation can be quickly forgotten if people do not keep talking about it.
Cambridge English vocab. Кембриджский английский словарь. 2012