- not
- adverb
1 used to make a word or expression negative: “Can we go to the park?” “No, not today, dear.” | Lorna was not a tidy child and left toys everywhere. | The store is open all week but not on Sundays. | Sally will not eat meat. | You were wrong not to inform the police. | not at all easy/difficult etc: I was not at all surprised to see her at the meeting. | not at all: I don't like his attitude at all.—compare no 1, —see also: n't, —see no 22 used instead of a word or expression to mean the opposite of something that has been mentioned before it: Are you ready to eat or not? | I hope to see you tomorrow, but if not, leave me a message. | hope/think/be afraid etc not: “Is Fiona coming?” “I hope not, she's so boring.” | I asked if she would be able to help out but she said not.—compare so 1 (4)3 used to give a word or expression the opposite meaning: “Will the journey take much longer?” “Oh, it's not far now.” | Madeline is such a caring person, not without problems of her own. | In the war years diptheria was not an uncommon disease. | They want a cheap service but they're not slow to complain if the trains break down. | not very tall/expensive etc (=fairly short, cheap etc): These teabags aren't very good, are they? | not a little/a few etc (=quite a lot): He drank not a little of the wine. | not a lot/much/many etc (=only a few/a little etc): It's a new remedy for hay fever which not many people have heard of.4 not a/not one not any person or thing: Since she went abroad she hasn't even written a letter, not one word! | not even a: Her face was stony, not even a smile. | not a single: He has none of his savings left, not a single penny!5 not at all especially BrE used to be polite when someone has thanked you or asked you to do something: “Would you mind helping me with my suitcase?” “Not at all.”6 not only used to say that besides someone doing one thing they have also done something else: not only...but (also)...: Shakespeare was not only a writer but also an actor. | not only do/will/can etc: Not only do the nurses want a pay increase, they want reduced hours as well.7 not that I care/not that it is important etc used to mean that you do not care, that it is not important etc: Sarah's found herself a new boyfriend - not that I care about it.8 - not! spoken used, especially by young people, to say that you really mean the opposite of what you have just said: I really like spending my Saturday afternoons tidying the house - not!—see also: not half half 3 (5), not to say say 1 (43) USAGE NOTE: NOT FORMALITY In spoken English and informal writing not is usually shortened to n't with is, are, was, were, has, have, had, do, does etc. Shall not becomes shan't, and will not becomes won't. (Note however that shan't is only used in British English). SPELLING The short form of not is n't not 'nt. Can with the full form not is written as one word: The two sides in the dispute still cannot reach an agreement. | I simply cannot understand what he's talking about.
Longman dictionary of contemporary English. 2004.