thud vs run into

thud is a noun but run into is not a noun.

Word	Noun	Adjective	Verb	Adverb
thud	Yes	No	Yes	No
run into	No	No	Yes	No

As verbs, run into is a hypernym of thud; that is, run into is a word with a broader meaning than thud:

Other hypernyms of thud include collide with, hit, impinge on, strike.

thud (noun)	run into (noun)
a heavy dull sound (as made by impact of heavy objects)

thud (verb)	run into (verb)
strike with a dull sound	collide violently with an obstacle
make a dull sound	hit against; come into sudden contact with
make a noise typical of an engine lacking lubricants	come together
	be beset by