Meaning

adjective unhurried and relaxed

adjective having a full and pleasing flavor through proper aging

adjective having attained to kindliness or gentleness through age and experience

originEtymology tree English mellow Proto-Indo-European *-yōs Proto-Indo-European *-tHós Proto-Indo-European *-istHos Proto-Germanic *-istaz Proto-West Germanic *-ist Old English -est Middle English -est English -est English mellowest From mellow + -est.

Etymology from Wiktionary, CC BY-SA 3.0