mast vs mizzen

mast and mizzen both are nouns.

Word	Noun	Adjective	Verb	Adverb
mast	Yes	No	No	No
mizzen	Yes	No	No	No

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

mast: a vertical spar for supporting sails
mizzen: third mast from the bow in a vessel having three or more masts; the after and shorter mast of a yawl, ketch, or dandy

Other hyponyms of mast include foremast, jigger, jiggermast, jury mast, mainmast, mizen, mizenmast, mizzenmast, topmast.

mast (noun)	mizzen (noun)
a vertical spar for supporting sails	third mast from the bow in a vessel having three or more masts; the after and shorter mast of a yawl, ketch, or dandy
any sturdy upright pole	fore-and-aft sail set on the mizzenmast
nuts of forest trees used as feed for swine
nuts of forest trees (as beechnuts and acorns) accumulated on the ground