A gimp is s sex slave or submissive, usually male. Such a person may be forced to wear a gimp suit.
The use of the term gimp to mean a submissive seems to have originated with the 1994 film Pulp Fiction directed by Quentin Tarantino, in which there was a character referred to as the Gimp and use of the phrase “bring out the gimp”. Interestingly, the term is rarely used by members of the BDSM community and is only really used by the wider non-SM community to mean a sex slave. The word gimp does have a much longer history of being used as a pejorative term for a person with a limp. It has been suggested in an Informed Consent forum that the phrase “bring out the gimp” was originally intended by the director as a slightly shocking term of general abuse (like calling someone a spastic). This was then misinterpreted by the audience as meaning a sex slave because the character was wearing a zipped hood. The phrase gimp mask, meaning a mask that blocks the eyes and/or prevents speech, also has these connotations of disability.