I. ˈble-mish transitive verb
Etymology: Middle English blemisshen, to damage, injure, sully, from Anglo-French blemiss-, stem of blemir, blesmir, from Old French, literally, to make pale by wounding, of Germanic origin; akin to Old High German blas ros horse with a blaze, Old Norse blesi blaze — more at blaze
Date: 14th century
: to spoil by a flaw
II. noun
Date: 1535
: a noticeable imperfection ; especially : one that seriously impairs appearance