Fatten \Fat"ten\, v. t. [imp. & p. p. {Fattened}; p. pr. & vb. n. {Fattining}.] [See {Fat}, v. t.] 1. To make fat; to feed for slaughter; to make fleshy or plump with fat; to fill full; to fat. 2. To make fertile and fruitful; to enrich; as, to fatten land; to fatten fields with blood. --Dryden.