1. Make relaxed
   "The massage loosened up her tense muscles";
   - relax, unstrain, unlax [informal, rare], unwind
    
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
   "He loosened up his muscles before hitting the gym";
   - limber up, warm up
    
4. Rest from work; become less busy, tense or anxious
   "He loosened up in the hot tub";
   - relax, unbend, unwind, decompress, slow down, take it easy
    
5. Cause to become unblocked
   "The medicine loosened up my nose in minutes!";
   - unstuff [informal]

Derived forms: loosening up, loosens up, loosened up

Type of: acquit, act, affect, bear, behave, carry, change state, comport, conduct, deport, disengage, do, exercise, free, turn, work out