1. Having a full, rounded shape: Monroe was eating a plump, juicy peach.
2. Slightly overweight or fat: Jake was a plump, or chubby, little boy.

1. To sit, fall, or to lie down in a sudden, awkward, or relaxed way: "When mother came home, Lenora was so tired that she took her shoes off and plumped down on the couch."
2. To shake or to hit something; such as, a pillow to make it fuller, softer, or rounder: "Shirley plumped her pillows and got into bed."