"sickly-looking; having an unhealthy, emaciated appearance," 1835, from past participle of the obsolete or dialectal verb peak "look sickly or thin, shrink, waste away" (1540s), which is perhaps from peak on the notion of "become pointed" through emaciation. Middle English had also a verb peken "to move dejectedly, slink" (mid-15c.), but the connection is uncertain. Related: Peakedness.
updated on March 30, 2022