Synonyms and related words :
abnormally, at infrequent intervals, few, hardly, hardly ever, incredibly, infrequently, irregularly, little, not often, occasional, occasionally, rare, rarely, scarce, scarcely, scarcely ever, seldom if ever, sparsely, sporadic, sporadically, uncommon, uncommonly, uncustomarily, unexpectedly, unfrequent, unfrequently, unnaturally, unoften, unordinarily, unusually, very seldom