WordWeb Online

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

1. Make loose or looser
   "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
    
4. Disentangle and raise the fibers of
   "loosen wool"
   - tease, tease apart
    
5. Cause to become loose
   "loosen the necktie"
   - untie, undo
    
6. Make less dense
   "loosen the soil"
    
7. Become loose or looser or less tight
   "The noose loosened"
   - relax, loose

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

Antonym: stiffen, tightening