Adjectival nouns or quasi-adjectives (keiyodoshi); 必用 can imply has to be used rather than is just needed

necessary; needed; essential; indispensable

Common noun

necessity; need; requirement

preparation; arrangements; provision; getting ready; laying out (e.g. a meal)

Common noun

business; task; errand; engagement

Common noun

use; purpose

Noun, used as a suffix

for the use of ...; used for ...; made for ...

Common noun

call of nature; excretion

use; utilization; utilisation; application

Noun or participle which takes the aux. verb suru; Transitive verb

confidence; trust; faith; reputation

Finance

credit

use; application; employment; utilization; utilisation

business; things to do; engagement; errand; affairs

to use; to make use of; to utilize; to utilise

skillful; skilful; adroit; dexterous; dextrous; deft; nimble; handy

clever; shrewd; ingenious

Common noun

(common) use (of a language, currency, etc.); current use; circulation; currency; validity (e.g. of a ticket)

to be accepted (e.g. of a way of thinking); to work (of an excuse, trick, etc.); to hold true (e.g. of a theory); to apply; to be valid; to pass (for); to do well; to get by

Common noun

going in and out; entrance and exit