US coin worth five cents (6)
I believe the answer is:
nickel
'us coin worth five cents' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for nickel that I've seen before include "very little money" , "not worth much in America" , "Five-cent coin (US)" , "One twentieth of a US dollar" , "American five cent piece" .)