THESAURUS
unbend
abate, bate, bend, disentangle, ease, ease off, ease up, extend, flatten, give, give way, let down, let up, let up on, loose, loosen, loosen up, mitigate, put straight, rectify, relax, relent, remit, set straight, sit up, slack, slack off, slack up, slacken, slake, slow down, smooth, stand up, straighten, straighten out, straighten up, submit, unbrace, uncurl, unkink, unlax, unsnarl, unstrain, unstring, unwind, yield
ROGET THESAURUS
unbend
Repose
VB
repose, rest, rest and be thankful, take a rest, take one's ease, take it easy, relax,
unbend, slacken, take breath, rest upon one's oars, pause, stay one's hand, lie down, recline, recline on a bed of down, recline on an easy chair, go to rest, go to bed, go to sleep, take a holiday, shut up shop, lie fallow.
Straightness
VB
be straight, have no turning, not incline to either side, not bend to either side, not turn to either side, not deviate to either side, go straight, steer for, render straight, straighten, rectify, set straight, put straight,
unbend, unfold, uncurl &c, unravel, unwrap.