One who gives a moving performance (6)
I believe the answer is:
dancer
'one who gives a moving performance' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'one' is the wordplay.
I cannot quite understand how this works, but
'one' could be 'an' (an apple is one apple) and 'an' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for dancer that I've seen before include "One in the same team as, say, Rudolf" , "Ballet performer" , "Craned (anag.)" , "See 25" , "Ballerina or chorus girl?" .)