Noun. 1.a good friend, pal, or buddy..chummy.adj. to be friendly.
2.Shark bait composed of unwanted or useless fish parts. chummed; chummer; chumming; ect.
3.SLANG.Semen or sebum see also "smegma".

Someone who used to be a potential girlfriend/boyfriend, but no longer is.

unwanted fish parts: guts fins and heads

Used by Edinburghian's (people from Edinburgh, Scotland). It means to accompany someone somewhere.

verb:
to chum, meaning hang out with, escort, keeping company. Scottish term.

Canadian French for boyfriend

The short form of "chumleg," referring to the penis. As the penis is also usually its owner's best friend, the friendliness implied by "chum" makes the term that much more appropriate.