mend vs trouble-shoot

mend is a noun but trouble-shoot is not a noun.

Word	Noun	Adjective	Verb	Adverb
mend	Yes	No	Yes	No
trouble-shoot	No	No	Yes	No

As verbs, trouble-shoot is a hyponym of mend; that is, trouble-shoot is a word with a more specific, narrower meaning than mend:

mend: restore by replacing a part or putting together what is torn or broken
trouble-shoot: solve problems

mend (noun)	trouble-shoot (noun)
the act of putting something in working order again
sewing that repairs a worn or torn hole (especially in a garment)

mend (verb)	trouble-shoot (verb)
restore by replacing a part or putting together what is torn or broken	solve problems
heal or recover