chopper vs ground ball

chopper and ground ball both are nouns.

Word	Noun	Adjective	Verb	Adverb
chopper	Yes	No	No	No
ground ball	Yes	No	No	No

As nouns, ground ball is a hypernym of chopper; that is, ground ball is a word with a broader meaning than chopper:

Other hypernyms of chopper include groundball, grounder, hopper.

chopper (noun)	ground ball (noun)
a grounder that bounces high in the air	(baseball) a hit that travels along the ground
a butcher's knife having a large square blade
an aircraft without wings that obtains its lift from the rotation of overhead blades
informal terms for a human `tooth'