refer vs dredge up

refer and dredge up both are verbs.

Word	Noun	Adjective	Verb	Adverb
refer	No	No	Yes	No
dredge up	No	No	Yes	No

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

refer (verb)	dredge up (verb)
think of, regard, or classify under a subsuming principle or with a general group or in relation to another	mention something unpleasant from the past
have as a meaning
make reference to
use a name to designate
seek information from
send or direct for treatment, information, or a decision
be relevant to