#1 straighten v. [unbend] straighten up or out; make straight. wn
#2 straighten v. [straighten out] make straight. wn
#3 straighten v. get up from a sitting or slouching position; "The students straightened when the teacher entered". wn
#4 straighten v. [tidy, tidy up, clean up, neaten, straighten out, square away] put (things or places) in order; "Tidy up your room!". wn
#5 straighten v. [roll out] straighten by unrolling; "roll out the big map". wn
vizzz