grenade thrower vs grenadier

grenade thrower and grenadier both are nouns.

Word	Noun	Adjective	Verb	Adverb
grenade thrower	Yes	No	No	No
grenadier	Yes	No	No	No

As nouns, grenade thrower and grenadier are synonyms defined as:

grenade thrower (noun)	grenadier (noun)
an infantryman equipped with grenades	deep-sea fish with a large head and body and long tapering tail
	an infantryman equipped with grenades