cheerful (adj.)youdaoicibaDictYouDict
c. 1400, "full of cheer," from cheer (n.) + -ful. Meaning "elevating the spirits" is from mid-15c. Related: Cheerfully; cheerfulness.
chirpy (adj.)youdaoicibaDictYouDict
"cheerfully perky," 1825, from chirp + -y (2). The notion is perhaps of birds fluttering and chattering.