used to make a word, phrase, or whole sentence negative
I am not ready yet.
They have not finished their homework.
✦ Old English "nōt", contraction of "ne wāt" meaning "does not know"; later generalized as the universal negative particle.
used in short answers to give a negative reply without repeating all the words of the question
"Will it rain today?" — "I hope not."
"Did you break the vase?" — "Certainly not!"
said after a statement to show that you are joking and actually mean the opposite
That was the best concert ever — not!
Oh yes, I love waking up at 5 a.m., not!
