"lively, in good spirits," a variant of pert (q.v.).
Entries linking to peart
pert adj.
mid-13c., "evident, unconcealed, manifest, apparent to the eye;" early 14c., "attractive, comely, of good appearance," shortened form of Middle English apert "open, frank," from Old French apert, from Latin apertus, past participle of aperire "to open" (see overt). Sense of "saucy, impudent" is recorded from late 14c. Less pejorative meaning "lively, brisk, in good spirits" (c. 1500) survives in U.S. dialectal peart (with Middle English alternative spelling). Related: Pertly; pertness.