course of action vs course

course of action and course both are nouns.

Word	Noun	Adjective	Verb	Adverb
course of action	Yes	No	No	No
course	Yes	No	Yes	Yes

As nouns, course of action and course are synonyms defined as:

course of action (noun)	course (noun)
a mode of action	a mode of action
	education imparted in a series of lessons or meetings
	facility consisting of a circumscribed area of land or water laid out for a sport
	(construction) a layer of masonry
	part of a meal served at one time
	a connected series of events or actions or developments
	a body of students who are taught together
	general line of orientation
	a line or route along which something travels or moves

course of action (adverb)	course (adverb)
	as might be expected