military machine vs operation

military machine and operation both are nouns.

Word	Noun	Adjective	Verb	Adverb
military machine	Yes	No	No	No
operation	Yes	No	No	No

military machine (noun)	operation (noun)
the military forces of a nation	a medical procedure involving an incision with instruments; performed to repair damage or arrest disease in a living body
	(mathematics) calculation by mathematical methods
	activity by a military or naval force (as a maneuver or campaign)
	a planned activity involving many people performing various actions
	a process or series of acts especially of a practical or mechanical nature involved in a particular form of work
	a business especially one run on a large scale
	the activity of operating something (a machine or business etc.)
	(psychology) the performance of some composite cognitive activity; an operation that affects mental contents
	(computer science) data processing in which the result is completely specified by a rule (especially the processing that results from a single instruction)
	process or manner of functioning or operating
	the state of being in effect or being operative