not in the least

adjective, a superl. of little with less or lesser as compar.

1. smallest in size, amount, degree, etc.; slightest: He gave the least amount of money of anyone.
2. lowest in consideration, position, or importance.

noun

3. something that is least; the least amount, quantity, degree, etc.
4. South Midland U.S. the youngest in a family or group.

adverb superl. of little with less as compar.

5. to the smallest extent, amount, or degree: That’s the least important question of all. He talks least.

Idioms

6. at least,
   1. at the lowest estimate or figure: The repairs will cost at least $100.
   2. at any rate; in any case: You didn’t get a good grade, but at least you passed the course.

   Also at the least.

7. not in the least, not in the smallest degree; not at all: I am not in the least concerned about the outcome of the World Series.

determiner

1. 1. the least the superlative of little you have the least talent of anyone
   2. (as pronoun; functioning as sing)least isn’t necessarily worst
2. at least
   1. if nothing elseyou should at least try
   2. at the least
3. at the least or at least at the minimumat the least you should earn a hundred pounds
4. in the least (usually used with a negative) in the slightest degree; at allI don’t mind in the least

adverb

5. the least superlative of little they travel the least of all

adjective

6. of very little importance or rank

adj.Old English læst, earlier læsest “smallest” (superlative of lytel “small”), from Proto-Germanic superlative *laisistaz (see less). Qualifying phrase at least is Middle English æt læstan. As a noun, from early 12c.; as an adverb, c.1200. see in the least. In addition to the idioms beginning with least

least of all

least resistance, line of

also see:

at least

in the least

last but not least

to say the least