adverb
a - used to form the negative of modal verbs (such as should and could) and auxiliary verbs (such as do and have)
b - used before a verb or clause to make it negative or give it an opposite meaning
a - used with a word or phrase to make it negative or give it an opposite meaning
b - used with a negative word to make a positive statement
c informal + humorous - used humorously at the end of a positive statement to show that you really meant the opposite
less or fewer than
used to refer to a possible situation, condition, etc., that is different from or opposite to another situation, condition, etc.
used to give a negative answer to a question
as like as not
or like as not
more often than not
happening more than half the time
not a/one
no thing or person
not that
used to say that something said before is not important