From WordNet (r) 3.0 (2006) [wn]:
acceptable
adj 1: worthy of acceptance or satisfactory; "acceptable levels
of radiation"; "performances varied from acceptable to
excellent" [ant: unacceptable]
2: judged to be in conformity with approved usage; "acceptable
English usage"
3: meeting requirements; "the step makes a satisfactory seat"
[syn: satisfactory, acceptable]
4: adequate for the purpose; "the water was acceptable for
drinking"
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Acceptable \Ac*cept"a*ble\ (-s[e^]pt"[.a]*b'l; 277), a. [F.
acceptable, L. acceptabilis, fr. acceptare.]
Capable, worthy, or sure of being accepted or received with
pleasure; pleasing to a receiver; gratifying; agreeable;
welcome; as, an acceptable present, one acceptable to us.
[1913 Webster]