least / lēst/ • adj. & pron. (usu. the least) smallest in amount, extent, or significance: [as adj.] who has the least money? he never had the least idea what to do about it [as pron.] how others see me is the least of my worries it's the least I can do. • adj. used in names of very small animals and plants, e.g., least shrew.• adv. to the smallest extent or degree: my best number was the one I had practiced the least turning up when he was least expected only the least expensive lot sold I never hid the truth, least of all from you.PHRASES: at least1. not less than; at the minimum: clean the windows at least once a week.2. if nothing else (used to add a positive comment about a generally negative situation): the options aren't complete, but at least they're a start.3. anyway (used to modify something just stated): they seldom complained—officially at least.at the least (or very least) 1. (used after amounts) not less than; at the minimum: stay ten days at the least.2. taking the most pessimistic or unfavorable view: a program that is, at the very least, excellent PR for the hospital.not in the least not in the smallest degree; not at all: he was not in the least taken aback.not least in particular; notably: there is a great deal at stake, not least in relation to the environment.to say the least used as an understatement (implying the reality is more extreme, usually worse): his performance was disappointing to say the least.