loosen

Short definition from Wiktionary

Verb

1. 1
   To make loose.
2. 2
   To become loose.
3. 3
   To disengage (a device that restrains).
4. 4
   To become unfastened or undone.
5. 5
   To free from restraint; to set at liberty.
6. 6
   To relieve (the bowels) from constipation; to promote defecation.
7. 7
   To create a breach or rift between (two parties).
8. 8
   To sail away (from the shore).