OK, acceptable, adequate, admissible, all right, allowable, average, bearable, better than nothing, betwixt and between, common, decent, dull, endurable, fair, fair to middling, fairish, good enough, goodish, indifferent, insipid, lackluster, livable, mediocre, medium, middling, moderate, modest, namby-pamby, not amiss, not bad, not half bad, not so bad, of a kind, of a sort, of sorts, okay, ordinary, passable, presentable, pretty good, respectable, run-of-the-mill, satisfactory, so-so, so so, sufferable, sufficient, supportable, sustainable, tedious, tidy, unexceptionable, unexceptional, unimpeachable, unobjectionable, vapid, wishy-washy, workmanlike