adj. mel·low·er, mel·low·est
a. Soft, sweet, juicy, and full-flavored because of ripeness: a mellow fruit.
b. Suggesting softness or sweetness: "The mellow air brought in the feel of imminent autumn" (Thomas Hardy).
2. Rich and soft in quality: a mellow sound; a mellow wine.
3. Having the gentleness, wisdom, or tolerance often characteristic of maturity.
4. Relaxed and unhurried; easygoing: a mellow friend; a mellow conversation.
a. Slightly and pleasantly intoxicated.
b. Pleasantly high from a drug, especially from smoking marijuana.
6. Moist, rich, soft, and loamy. Used of soil.
tr. & intr.v. mel·lowed, mel·low·ing, mel·lows
To make or become mellow.
mellow out Slang
To become genial and pleasant; relax: "The cowboy mellowed out when they read him a sweet letter from his wife" (Bobbie Ann Mason).http://www.thefreedictionary.com/mellow