Definition of Jack Strop in English:

Jack Strop

noun

nautical slang Military
  • A conceited or obstreperous sailor; a know-all.

    Earlier currency is perhaps implied by the name Jack Strop, given to the character of a sailor in a comic sketch performed by the crew of HMS Rattler, though the name is perhaps derived from "strop".

Origin

Early 20th century; earliest use found in Englishman. Perhaps from strop.