Synonyms/Hypernyms (Ordered by Estimated Frequency) of noun surplus

1 sense of surplus

Sense 1
excess, surplus, surplusage, nimiety -- (a quantity much larger than is needed)
       => overabundance, overmuch, overmuchness, superabundance -- (a quantity that is more than what is appropriate; "four-year-olds have an overabundance of energy"; "we received an inundation of email")

Antonyms of adj surplus

1 sense of surplus

Sense 1
excess, extra, redundant, spare, supererogatory, superfluous, supernumerary, surplus -- (more than is needed, desired, or required; "trying to lose excess weight"; "found some extra change lying on the dresser"; "yet another book on heraldry might be thought redundant"; "skills made redundant by technological advance"; "sleeping in the spare room"; "supernumerary ornamentation"; "it was supererogatory of her to gloat"; "delete superfluous (or unnecessary) words"; "extra ribs as well as other supernumerary internal parts"; "surplus cheese distributed to the needy")

INDIRECT (VIA unnecessary) -> necessary -- (absolutely essential)

Similarity of adj surplus

1 sense of surplus

Sense 1
excess, extra, redundant, spare, supererogatory, superfluous, supernumerary, surplus -- (more than is needed, desired, or required; "trying to lose excess weight"; "found some extra change lying on the dresser"; "yet another book on heraldry might be thought redundant"; "skills made redundant by technological advance"; "sleeping in the spare room"; "supernumerary ornamentation"; "it was supererogatory of her to gloat"; "delete superfluous (or unnecessary) words"; "extra ribs as well as other supernumerary internal parts"; "surplus cheese distributed to the needy")
       => unnecessary (vs. necessary), unneeded -- (not necessary)