It gets an athlete nowhere (3)
I believe the answer is:
lap
'athlete nowhere' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
'it gets an' is the wordplay.
'it' becomes 'lp' (I can't justify this - if you can you should believe this answer much more).
'gets' is an insertion indicator (gets can mean captures or absorbs).
'an' becomes 'a'.
'lp' placed around 'a' is 'LAP'.
Can you help me to learn more?
(Other definitions for lap that I've seen before include "One circuit of track" , "A circuit of a racecourse" , "Sports circuit" , "400 metres, typically" , "Single circuit of track" .)