undo vs unknot

undo and unknot both are verbs.

Word	Noun	Adjective	Verb	Adverb
undo	No	No	Yes	No
unknot	No	No	Yes	No

As verbs, unknot is a hyponym of undo; that is, unknot is a word with a more specific, narrower meaning than undo:

undo: cancel, annul, or reverse an action or its effect
unknot: become or cause to become undone by separating the fibers or threads of

undo (verb)	unknot (verb)
cancel, annul, or reverse an action or its effect	become or cause to become undone by separating the fibers or threads of
cause to become loose
remove the outer cover or wrapping of
deprive of certain characteristics
cause the ruin or downfall of