refresher course vs refresher

refresher course and refresher both are nouns.

Word	Noun	Adjective	Verb	Adverb
refresher course	Yes	No	No	No
refresher	Yes	No	No	No

As nouns, refresher course and refresher are synonyms defined as:

refresher course and refresher: a course that reviews and updates a topic for those who have not kept abreast of developments

refresher course (noun)	refresher (noun)
a course that reviews and updates a topic for those who have not kept abreast of developments	a course that reviews and updates a topic for those who have not kept abreast of developments
	a drink that refreshes
	a fee (in addition to that marked on the brief) paid to counsel in a case that lasts more than one day