flicker vs move back and forth

flicker is a noun but move back and forth is not a noun.

Word	Noun	Adjective	Verb	Adverb
flicker	Yes	No	Yes	No
move back and forth	No	No	Yes	No

As verbs, move back and forth is a hypernym of flicker; that is, move back and forth is a word with a broader meaning than flicker:

flicker: move back and forth very rapidly
move back and forth: move in one direction and then into the opposite direction

flicker (noun)	move back and forth (noun)
the act of moving back and forth
North American woodpecker
a momentary flash of light

flicker (verb)	move back and forth (verb)
move back and forth very rapidly	move in one direction and then into the opposite direction
flash intermittently
shine unsteadily