instant replay vs action replay

instant replay and action replay both are nouns.

Word	Noun	Adjective	Verb	Adverb
instant replay	Yes	No	No	No
action replay	Yes	No	No	No

As nouns, instant replay and action replay are synonyms defined as:

instant replay and action replay: the immediate rebroadcast of some action (especially sports action) that has been recorded on videotape

Other synonyms of instant replay include replay.

instant replay (noun)	action replay (noun)
the immediate rebroadcast of some action (especially sports action) that has been recorded on videotape	the immediate rebroadcast of some action (especially sports action) that has been recorded on videotape