Q: How did “peaked,” an adjective describing a high point, come to be an adjective describing a sickly person at a low point?
A: The sickly sense of the word “peaked” refers to the sharp, thin, pinched features (that is, the peak-like appearance) of someone who’s ill or poorly fed.
This sense of the word first showed up in print in the early 19th century, according to published references in the Oxford English Dictionary.
The earliest citation comes from an 1809 issue of the publication Transactions of the American Philosophical Society: “We say (in the United-States) of a person whose face is contracted by sickness, he looks peaked.”
The usage was preceded by several similar terms: “peakingly” (1611), “peaking” (1699), and “peakingness” (1727), but these are now considered either obsolete or regional.
However, the colloquial term “peaky” (1823) is still seen quite a bit, though “peakyish” (1853) shows up rarely these days.
“Peaked,” the adjective describing an actual peak, entered English in the mid-1300s. An etymology note in the OED says the adjective apparently comes from the noun “peak,” though the noun didn’t show up in print until the mid-1400s.
By the way, the sickly adjective is usually pronounced PEE-kid and the geographic one PEEKT, though some dictionaries give both pronunciations for both words.
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