coinage vs portmanteau

coinage and portmanteau both are nouns.

Word	Noun	Adjective	Verb	Adverb
coinage	Yes	No	No	No
portmanteau	Yes	No	No	No

As nouns, portmanteau is a hyponym of coinage; that is, portmanteau is a word with a more specific, narrower meaning than coinage:

coinage: a newly invented word or phrase
portmanteau: a new word formed by joining two others and combining their meanings

Other hyponyms of coinage include blend, portmanteau word.

coinage (noun)	portmanteau (noun)
the act of inventing a word or phrase	a large travelling bag made of stiff leather
a newly invented word or phrase	a new word formed by joining two others and combining their meanings
coins collectively