Stiff
Old English stīf, of Germanic origin; related to Dutch stijf .
wiktionary
From Middle English stiff, stiffe, stif, from Old English stīf, from Proto-Germanic *stīfaz (compare West Frisian stiif, Dutch stijf, Norwegian Bokmål stiv, German steif), from Proto-Indo-European *steypós (compare Latin stīpes, stīpō, from which English stevedore).
etymonline
stiff (adj.)
Old English stif "rigid, inflexible," from Proto-Germanic *stifaz "inflexible" (source also of Dutch stijf, Old High German stif, German steif "stiff;" Old Norse stifla "choke"), from PIE *stipos-, from root *steip- "press together, pack, cram" (source also of Sanskrit styayate "coagulates," stima "slow;" Greek stia, stion "small stone," steibo "press together;" Latin stipare "pack down, press," stipes "post, tree trunk;" Lithuanian stipti "to stiffen, grow rigid," stiprus "strong;" Old Church Slavonic stena "wall"). Of battles and competitions, from mid-13c.; of liquor, from 1813. To keep a stiff upper lip is attested from 1815. Related: Stiffly.
stiff (n.)
"corpse, dead body," 1859, slang, from stiff (adj.) which had been associated with notion of rigor mortis since c. 1200. Meaning "working man" first recorded 1930, from earlier genitive sense of "contemptible person," but sometimes merely "man, fellow" (1882). Slang meaning "something or someone bound to lose" is 1890 (originally of racehorses), from notion of "corpse."
stiff (v.)
late 14c., "to make stiff," from stiff (adj.). Meaning "fail to tip" is from 1939, originally among restaurant and hotel workers, probably from stiff (n.), perhaps in slang sense of "corpse" (because dead men pay no tips), or from the "contemptible person" sense. Extended by 1950 to "cheat."