1 tr. & intr. make or become less tight or compact or firm.
2 tr. make (a regime etc.) less severe.
3 tr. release (the bowels) from constipation.
4 tr. relieve (a cough) from dryness.
Phrases and idioms:
loosen a person's tongue make a person talk freely. loosen up = limber up (see LIMBER(1)).
Derivatives:
loosener n.
Useful english dictionary. 2012.