Old English stearc "stiff, strong, rigid, obstinate; stern, severe, hard; harsh, rough, violent," from Proto-Germanic *starka- (source also of Old Norse sterkr, Danish, Old Frisian sterk, Middle Dutch starc, Old High German starah, German stark, Gothic *starks), from PIE root *ster- (1) "stiff." From the same root as stern (adj.).
Meaning "utter, sheer, complete" first recorded c. 1400, perhaps from influence of common phrase stark dead (late 14c.), with stark mistaken as an intensive adjective. Sense of "bare, barren" is from 1833. As an adverb from c. 1200. Related: Starkly; starkness. Stark-raving (adj.) is from 1640s; earlier stark-staring 1530s.