adj

• (obsolete) Exhibiting the qualities of a fat animal; coarse; heavy; gross; dull; stupid.
  "Make the heart of this people fat,[…]"
• (dated, printing) Of a character which enables the compositor to make large wages; said of matter containing blank, cuts, or many leads, etc.
  "a fat take; a fat page"
• (golf) Being a shot in which the ground is struck before the ball.
  "Hitting a thin shot from a fairway bunker is more productive than hitting a fat shot."
• (theater) Of a role: significant; major; meaty.
  "He is what the theatre calls a “fat” role — a man suddenly confronted by a terrible duty. He is called upon to revenge the murder of his father and to right a wrong against the state."

noun

• (uncountable) A specialized animal tissue with high lipid content, used for long-term storage of energy: fat tissue.
  "Mammals that hibernate have plenty of fat to keep them warm during the winter."
• (uncountable) A specialized animal tissue with high lipid content, used for long-term storage of energy: fat tissue.
  "Ask the butcher for a few pounds of fat for our greens."
• (countable) A lipid that is solid at room temperature, which fat tissue contains and which is also found in the blood circulation; sometimes, a refined substance chemically resembling such naturally occurring lipids.
  "Dietary fat is not the evil that it was once misapprehended to be; carbs are increasingly recognized as a bigger driver of atherosclerosis via chronic insulin resistance and the vascular processes that cascade from it."
• (slang) An erection.
  "I saw Daniel crack a fat."

verb

• (transitive, archaic) To make fat; to fatten.
  "kill the fatted calf"
• (intransitive, archaic) To become fat; to fatten.
• (transitive, golf) To hit (a golf ball) with a fat shot.
  "“On this one hole, Donald hits his second and fats it into the water,” Faxon remembers. “But he quickly says to me, ‘Hey, throw me another ball; they weren’t looking.’ So I do. But he fats that one into the water, too. So he drives up and drops where he should’ve dropped the first time and hits it on the green.”"

noun

• (obsolete) A large tub or vessel for water, wine, or other liquids; a cistern.
  "And the floores ſhall bee full of wheate, and the fats ſhall ouerflowe with wine and oyle."
• (obsolete) A dry measure, generally equal to nine bushels.