fatten

Short definition from Wiktionary

Verb

1. 1
   To cause (a person or animal) to be fat or fatter.
2. 2
   To become fat or fatter.
3. 3
   To make thick or thicker (often something containing paper, especially money).
4. 4
   To become thick or thicker.
5. 5
   To make (soil) fertile and fruitful.
6. 6
   To become fertile and fruitful.