fieldwork vs munition

fieldwork and munition both are nouns.

Word	Noun	Adjective	Verb	Adverb
fieldwork	Yes	No	No	No
munition	Yes	No	Yes	No

As nouns, munition is a hypernym of fieldwork; that is, munition is a word with a broader meaning than fieldwork:

fieldwork: a temporary fortification built by troops in the field
munition: defensive structure consisting of walls or mounds built around a stronghold to strengthen it

Other hypernyms of fieldwork include fortification.

fieldwork (noun)	munition (noun)
a temporary fortification built by troops in the field	weapons considered collectively
	defensive structure consisting of walls or mounds built around a stronghold to strengthen it
	military supplies

fieldwork (verb)	munition (verb)
	supply with weapons