Synonyms/Hypernyms (Ordered by Estimated Frequency) of verb need

3 senses of need

Sense 1
necessitate, ask, postulate, need, require, take, involve, call for, demand -- (require as useful, just, or proper; "It takes nerve to do what she did"; "success usually requires hard work"; "This job asks a lot of patience and skill"; "This position demands a lot of personal sacrifice"; "This dinner calls for a spectacular dessert"; "This intervention does not postulate a patient's consent")

Sense 2
want, need, require -- (have need of; "This piano wants the attention of a competent tuner")
       => be -- (have the quality of being; (copula, used with an adjective or a predicate noun); "John is rich"; "This is not a good answer")

Sense 3
need -- (have or feel a need for; "always needing friends and money")

Antonyms of adj needed

1 sense of needed

Sense 1
needed, needful, required, requisite -- (necessary for relief or supply; "provided them with all things needful")

INDIRECT (VIA necessary) -> unnecessary, unneeded -- (not necessary)

Similarity of adj needed

1 sense of needed

Sense 1
needed, needful, required, requisite -- (necessary for relief or supply; "provided them with all things needful")
       => necessary (vs. unnecessary) -- (absolutely essential)