WordWeb Online

1. Cause to become unblocked
   "The medicine loosened up my nose in minutes!"
   - unstuff
    
2. Become less tense, less formal, or less restrained, and assume a friendlier manner
   "our new colleague loosened up when he saw that we were a friendly group"
   - relax
    
3. Make one's body limber or suppler by stretching, as if to prepare for strenuous physical activity
   - limber up, warm up
    
4. Become less tense, rest, or take one's ease
   "He loosened up in the hot tub"
   - relax, unbend, unwind, decompress, slow down
    
5. Cause to feel relaxed
   - relax, unstrain, unlax, unwind, make relaxed

Derived forms: loosening up, loosened up, loosens up

Type of: act, affect, behave, change state, disengage, do, exercise, free, turn, work out