1.straighten up or out; make straight
2.unfasten, as a sail, from a spar or a stay
3.free from flexure;
unbend a bow
4.make less tight;
relax the tension on the rope
5.become less tense, rest, or take one's ease;
He relaxed in the hot tub
6.release from mental strain, tension, or formality;
unbend the mind from absorbing too much information