countersuit vs lawsuit

countersuit and lawsuit both are nouns.

Word	Noun	Adjective	Verb	Adverb
countersuit	Yes	No	No	No
lawsuit	Yes	No	No	No

As nouns, lawsuit is a hypernym of countersuit; that is, lawsuit is a word with a broader meaning than countersuit:

countersuit: a suit brought against someone who has sued you
lawsuit: a comprehensive term for any proceeding in a court of law whereby an individual seeks a legal remedy

Other hypernyms of countersuit include case, causa, cause, suit.

countersuit (noun)	lawsuit (noun)
a suit brought against someone who has sued you	a comprehensive term for any proceeding in a court of law whereby an individual seeks a legal remedy