ambusher vs assaulter

ambusher and assaulter both are nouns.

Word	Noun	Adjective	Verb	Adverb
ambusher	Yes	No	No	No
assaulter	Yes	No	No	No

As nouns, assaulter is a hypernym of ambusher; that is, assaulter is a word with a broader meaning than ambusher:

ambusher: an attacker who waits in a concealed position to launch a surprise attack
assaulter: someone who attacks

Other hypernyms of ambusher include aggressor, assailant, attacker.

ambusher (noun)	assaulter (noun)
an attacker who waits in a concealed position to launch a surprise attack	someone who attacks