Jeep
Second World War (originally US): from the initials GP, standing for general purpose, influenced by ‘Eugene the Jeep’, a creature of great resourcefulness and power represented in the Popeye comic strip.
wiktionary
Derived from GP, initialism of general-purpose. Noun from General Purpose Vehicle (military light utility truck).
Disputed. Possibly from Eugene the Jeep, a character in Popeye cartoons. [1]
etymonline
jeep (n.)
early 1941, American English military slang, acronym from G.P., abbreviation of General Purpose (car), but certainly influenced by Eugene the Jeep (who had extraordinary powers but said only "jeep"), from E.C. Segar's comic strip "Thimble Theater" (home of Popeye the Sailor). Eugene the Jeep first appeared in the strip March 13, 1936. The vehicle was in development from 1940, and the Army planners' initial term for it was light reconnaissance and command car.