hollo vs pipe up

hollo is a noun but pipe up is not a noun.

Word	Noun	Adjective	Verb	Adverb
hollo	Yes	No	Yes	No
pipe up	No	No	Yes	No

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

hollo (noun)	pipe up (noun)
a very loud utterance (like the sound of an animal)

hollo (verb)	pipe up (verb)
utter a sudden loud cry	begin to play or sing
cry hollo	utter a shrill cry
encourage somebody by crying hollo