a person or thing that hops.

Informal . a person who travels or moves frequently from one place or situation to another (usually used in combination)

a two-week tour designed for energetic city-hoppers.

any of various jumping insects, as grasshoppers or leafhoppers.

Australian . kangaroo.

a funnel-shaped chamber or bin in which loose material, as grain or coal, is stored temporarily, being filled through the top and dispensed through the bottom.

Railroads . hopper car.

U.S. Politics . a box into which a proposed legislative bill is dropped and thereby officially introduced.

one of the pieces at each side of a hopper casement. ?

in the hopper

Informal . in preparation; about to be realized

Plans for the class reunion are in the hopper.