Necessary; obligatory; mandatory.

simple past tense and past participle of require

Capable of being required.

A person who requires.

plural of requiring

plural of requirer

plural of requirement

A necessity or prerequisite; something required or obligatory. Its adpositions are generally of in relation to who or what has given it, on in relation to whom or what it is given to, and for in relation to what is required.

(archaic) A requirement.

present participle of require