damp vs hold in

damp is a noun but hold in is not a noun.

Word	Noun	Adjective	Verb	Adverb
damp	Yes	Yes	Yes	No
hold in	No	No	Yes	No

As verbs, hold in is a hypernym of damp; that is, hold in is a word with a broader meaning than damp:

damp: restrain or discourage
hold in: lessen the intensity of; temper; hold in restraint; hold or keep within limits

Other hypernyms of damp include check, contain, control, curb, hold, moderate.

damp (noun)	hold in (noun)
a slight wetness

damp (adjective)	hold in (adjective)
slightly wet

damp (verb)	hold in (verb)
lessen in force or effect	hold back; keep from being perceived by others
make vague or obscure or make (an image) less visible	lessen the intensity of; temper; hold in restraint; hold or keep within limits
restrain or discourage	close in
deaden (a sound or noise), especially by wrapping