To strike, beat.

(especially of a sound, flavour, or colour) pleasantly smooth or soft; free from harshness

she was hypnotized by the mellow tone of his voice

slow cooking gives the dish a sweet, mellow flavour

(of a person's character) tempered by maturity or experience

a more mellow personality

(of earth) rich and loamy

to most farmers, soil has good tilth when it is mellow and granular and crumbles easily in the hand

make or become mellow

even a warm sun could not mellow the North Sea breeze

fuller-flavoured whiskies mellow with wood maturation