Synonyms for Sufficient:

adj.

enough, adequate (adjective)
ample, plenty, common, acceptable, satisfactory, plenteous, decent, tolerable, plentiful, comfortable.
sufficient (adjective)
adequate, satisfactory, abundant, bountiful, plenteous, ample, plentiful, prosperous, enough.

n.

plenty, just enough, I'm all set, go around. excess. common, all-right, fairish, goodish, O.K., passable, good, moderate, tolerable, respectable, fair, tidy, average, acceptable. enough (noun)
study at enough.
sufficient (noun)
spare, adequate, decent, enough, comfortable.

Other synonyms:

goodish, fairish. go around, plenty. all-right, average, acceptable, tidy, passable, tolerable. respectable. common. moderate. fair. adequate
good.
Other relevant words:
fair, decent, average, acceptable, excess, plenty, moderate, spare, common, passable, respectable, tidy, tolerable, comfortable, good, goodish, fairish.

Usage examples for sufficient

  1. But such a fact is not sufficient – An Interpretation of Rudolf Eucken's Philosophy by W. Tudor Jones
  2. This explanation was sufficient for them. – French and Oriental Love in a Harem by Mario Uchard
  3. I trust my 'onor is sufficient in his respect. – Wych Hazel by Susan and Anna Warner