fatten up

present singular third person fattens up · participle present fattened up · participle past fattening up · past fattening up

1. transitiveTo cause to gain weight by means of feeding.

   I visited my mother for a month, and she managed to fatten me up 20 pounds.

   1 more example

   My cat looks underweight, so I'll fatten him up with higher-calorie cat food.

2. intransitiveTo become fat or fatter by gaining weight.

   ‘And isn’t Declan looking very thin?’ Madge said. ‘He’ll never get a wife if he doesn’t fatten up a bit.’

   1999, Colm Tóibín, chapter 8, in The Blackwater Lightship, New York: Scribner, page 246

3. figurativelytransitiveTo make bigger; to expand.

   We must not fatten up our payroll with people performing nonessential activities.

   1954, United States. Congress. House. Committee on Appropriations, Department of the Army Appropriations for 1955: Hearings, page 161