Real Dictionary

not
adverb: You use not with verbs to form negative statements.

not in American English
in no manner; to no degree
adverb: (used to express negation, denial, refusal, or prohibition)
noun: a Boolean operator that returns a positive result if its operand is negative and a negative result if its operand is positive

not in British English
adverb: used to negate the sentence, phrase, or word that it modifies

not- in American English
noto-
combining form

not- in British English
combining form