(1):

(v. i.) To grow fat or corpulent; to grow plump, thick, or fleshy; to be pampered.

(2):

(v. t.) To make fat; to feed for slaughter; to make fleshy or plump with fat; to fill full; to fat.

(3):

(v. t.) To make fertile and fruitful; to enrich; as, to fatten land; to fatten fields with blood.