abseil vs rope down

abseil is a noun but rope down is not a noun.

Word	Noun	Adjective	Verb	Adverb
abseil	Yes	No	Yes	No
rope down	No	No	Yes	No

As verbs, abseil and rope down are synonyms defined as:

Other synonyms of abseil include rappel.

abseil (noun)	rope down (noun)
(mountaineering) a descent of a vertical cliff or wall made by using a doubled rope that is fixed to a higher point and wrapped around the body

abseil (verb)	rope down (verb)
descend by means of a rappel	descend by means of a rappel