(1):

(adv.) Very; with a tendency to darkness of color.

(2):

(adv.) Profoundly; thoroughly; not superficially; in a high degree; intensely; as, deeply skilled in ethics.

(3):

(adv.) At or to a great depth; far below the surface; as, to sink deeply.

(4):

(adv.) With profound skill; with art or intricacy; as, a deeply laid plot or intrigue.

(5):

(adv.) Gravely; with low or deep tone; as, a deeply toned instrument.