Jemmy

a popular pet form of the masc. proper name James (in Middle English records, Gemme, Jemme are more common than Jimme). In mid-18c. often associated with effeminacy and male fastidiousness; hence jemmy (adj.) "spruce, neat" (1750), jemminess (1756). As "a short crowbar," favored by burglars, from 1811. Compare jimmy (n.).