WordNet sense 1 (unhurried and relaxed):

laid-back

WordNet sense 2 (without strain or anxiety):

relaxed

WordNet sense 3 (having a full and pleasing flavor through proper aging):

mellowed

WordNet sense 4 (fully developed or matured and ready to be eaten or used):

ripe

WordNet sense 5 (compassionate and kind; conciliatory):

soft

WordNet sense 6 (slightly and pleasantly intoxicated from alcohol or a drug (especially marijuana)):

high

WordNet sense 7 (stupefied or excited by a chemical substance (especially alcohol)):

drunk, inebriated, intoxicated

WordNet sense 8 ((obsolete) in a mellow manner):

mellowly

WordNet sense 9 (become more relaxed, easygoing, or genial):

melt, mellow out