shifter vs gearshift

shifter and gearshift both are nouns.

Word	Noun	Adjective	Verb	Adverb
shifter	Yes	No	No	No
gearshift	Yes	No	No	No

As nouns, shifter and gearshift are synonyms defined as:

shifter and gearshift: a mechanical device for engaging and disengaging gears

Other synonyms of shifter include gear lever, gearstick.

shifter (noun)	gearshift (noun)
a mechanical device for engaging and disengaging gears	a mechanical device for engaging and disengaging gears
a stagehand responsible for moving scenery