loosen

verb

1.
make loose or looser
unfast loose
Antonym:
stiffen
Derived from:
loosening
2.
make less severe or strict
relax
3.
become less severe or strict
unclench relax
4.
disentangle and raise the fibers of
tease tease apart
5.
cause to become loose
leese ungird undo untie
Derived from:
loosening
6.
make less dense
7.
become loose or looser or less tight
loose relax
Antonym:
stiffen
Derived from:
loosening