I've always been partial to Royal Naval slang, which is colourful and expressive. I have probably forgotten more than I remember, but some of the notable expressions are:-
"Hoggin" - short for hogwash, i.e. the sea
"Killick" - a leading hand, e.g, a "killick sparks" was a Leading Telegraphist" (actually a radio operator). The Petty Officer Telegraphist, naturally enough, was known as POTS. Seamen involved with visual signals were know as "Flags" or "Bunty" (for "bunting").
Stokers were always referred to as being "hairy-eared"
(actually, it wasn't their ears that were mentioned, but an entirely lower area of their anatomy - but delicacy forbids, etc)
Whenever a feast was arranged - usually on shore, rather than on board - it was referred to as "Big Eats!"
Another endearing habit of the RN was to issue the order "lash up and stow" soon afgter reveille, right on into the 1960s (possibly even into the 70s), long after safe, comfortable hammocks had been replaced by highly uncomfortable bunks
There are hundreds more - and they changed from time to time, of course, so that you may tell when an ex-matelot served by the slang he uses.
Anmd this is not even touching on the topic of nick-names! That almost deserves a thread of its own.
