drunkard vs boozer

drunkard and boozer both are nouns.

Word	Noun	Adjective	Verb	Adverb
drunkard	Yes	No	No	No
boozer	Yes	No	No	No

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

Other hyponyms of drunkard include alcoholic, alky, dipsomaniac, lush, soaker, souse.

drunkard (noun)	boozer (noun)
a chronic drinker	a person who drinks alcohol to excess habitually