Why "jimmy a lock?"--(was: Jimmies in NY?)

[Gerald Cohen]

At 1:40 PM -0400 7/6/04, Carolina Jimenez-Marcos wrote:
>Another question, why do thieves jimmy a lock?

   The instrument (a short crowbar) is a jimmy, so the question
becomes: why is the instrument so called?

     The answer is apparently unknown, but note 19th century cant
"neddy" (a club; apparently from Cockney rhyming slang "Uncle Ned" =
head).

    Similarly, note 19th century British cant "jemmy" (crowbar;
Americanized to "jimmy"), which I believe may derive from Cockney
rhyming slang "Jem" from "Jem Mace" (= face). In the 1860's memoirs
of  a London thief is an incident in which the author and his pal Joe
try to burglarize a home at night while the family is asleep. But the
husband--a big fellow--wakes up and comes out of his room towards the
two burglars. Joe wastes no time and clobbers the fellow in the face
with his "jemmy," dropping him instantly and thereby permitting the
two to escape.

    This sort of criminal context might have provided the start for
"jemmy", although, of course, its usual purpose is to pry things open.

Gerald Cohen