- Noun. (uncountable, grammar) The grammatical mood expressing an order (see jussive). In English, the imperative form of a verb is the same as that of the bare infinitive.
- Noun. (countable, grammar) A verb in imperative mood.
- Noun. (countable) An essential action, a must: something which is imperative.
- Adjective. essential.
- Adjective. (computing theory) Having a semantics that incorporates mutable variables.