straighten vs rise up

straighten and rise up both are verbs.

Word	Noun	Adjective	Verb	Adverb
straighten	No	No	Yes	No
rise up	No	No	Yes	No

As verbs, rise up is a hyponym of straighten; that is, rise up is a word with a more specific, narrower meaning than straighten:

Other hyponyms of straighten include rear, draw up, pull up, straighten up.

straighten (verb)	rise up (verb)
put (things or places) in order	come to the surface
make straight or straighter	stand up on the hind legs, of quadrupeds
make straight	take part in a rebellion; renounce a former allegiance
straighten by unrolling
straighten up or out; make straight
get up from a sitting or slouching position