firm up

verb5

1. •
   To make (muscles) more toned through physical exercise.

   • He hopes to firm up his biceps a bit before meeting the girls.
2. •
   To make (tentative plans) more definite.

   • Can we firm up plans for the barbecue Sunday?
3. •
   To become more definite.

   • Let me know as soon as your plans firm up.
4. •
   To become more toned through physical exercise.

   • After weeks of working out, his biceps finally began to firm up a bit.
5. •
   To become firmer in consistency.

   • Cook the omelet until the top has started to firm up.