hop-picker vs hopper

hop-picker and hopper both are nouns.

Word	Noun	Adjective	Verb	Adverb
hop-picker	Yes	No	No	No
hopper	Yes	No	No	No

As nouns, hop-picker and hopper are synonyms defined as:

hop-picker (noun)	hopper (noun)
a machine used for picking hops	(baseball) a hit that travels along the ground
	terrestrial plant-eating insect with hind legs adapted for leaping
	funnel-shaped receptacle; contents pass by gravity into a receptacle below
	a machine used for picking hops
	someone who hops