trench warfare vs warfare

trench warfare and warfare both are nouns.

Word	Noun	Adjective	Verb	Adverb
trench warfare	Yes	No	No	No
warfare	Yes	No	No	No

As nouns, warfare is a hypernym of trench warfare; that is, warfare is a word with a broader meaning than trench warfare:

trench warfare: a struggle (usually prolonged) between competing entities in which neither side is able to win
warfare: an active struggle between competing entities

Other hypernyms of trench warfare include war.

trench warfare (noun)	warfare (noun)
a type of armed combat in which the opposing troops fight from trenches that face each other	the waging of armed conflict against an enemy
a struggle (usually prolonged) between competing entities in which neither side is able to win	an active struggle between competing entities