What is a synonym for not?

Here are some synonyms for "not," depending on the context:

General Negation:

* No

* Never

* None

* Neither

* Without

* Lacking

* Absent

* Empty (for lack of something)

Formal Negation:

* Negation

* Denial

* Refutation

* Contradiction

Informal Negation:

* Nope

* Nah

* Ain't (informal, avoid in formal writing)

Specific Contexts:

* Don't (for verbs)

* Can't (for ability)

* Shouldn't (for obligation)

* Didn't (for past tense)

The best synonym for "not" will depend on the specific sentence and the desired tone.