WordWeb Online

1. An occurrence of control or strength weakening
   "the loosening of his grip";
   - relaxation, slackening, softening
    
2. The act of making something less tight
   - laxation

1. Make less tight or stiff
   "loosen the tension on a rope";
   - loose
    
2. Make less severe or strict
   "The government loosened the curfew after most of the rebels were caught";
   - relax
    
3. Become less severe or strict
   "The rules loosened after the new director arrived";
   - relax, soften
    
4. Disentangle and raise the fibers of
   "loosen wool";
   - tease, tease apart
    
5. Make less dense
   "loosen the soil"
    
6. Become loose, looser or less tight
   "The noose loosened";
   - relax, loose

Type of: adjustment, alter, alteration, change, disentangle, modification, modify, straighten out, unsnarl, weaken, weakening

Antonym: tightening