cramp (n.) "involuntary and painful muscle contraction," late 14c., from Old French crampe (13c.), from a Frankish or other Germanic word (compare Old High German krapmhe "cramp, spasm," related to kramph "bent, crooked"), from Proto-Germanic kramp-, forming many words for "bent, crooked," including, via French, crampon. early 15c., "metal bar bent at both ends," from Middle Dutch crampe or Middle Low German krampe, from Proto-Germanic kramp-. Metaphoric sense of "something that confines or hinders" is attested by 1719.