verb (used with object)
- to make fat.
- to feed (animals) abundantly before slaughter.
- to enrich: to fatten the soil; to fatten one’s pocketbook.
- Cards.
- Poker.to increase the number of chips in (a pot).
- Pinochle.to play a card that scores high on (a trick) expected to be taken by a partner.
verb (used without object)
- to grow fat.
verb
- to grow or cause to grow fat or fatter
- (tr) to cause (an animal or fowl) to become fat by feeding it
- (tr) to make fuller or richer
- (tr) to enrich (soil) by adding fertilizing agents
1550s, from fat + -en (1). Related: Fattened. The earlier verb was simply fat (Old English fættian “to become fat, fatten”); e.g. fatted calf.