"cheerfully perky," literally "full of chirping," 1825, from chirp + -y (2). The notion is perhaps of birds fluttering and chattering.
looking bright and well and chirpy
his quick wit and chirpy humor
chiropodist
chiropractic
chiropractor
chirosophy
chirp
chirpy
chirr
chirrup
chirurgeon
chisel
chiseled
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