If you want a pin-up, move fast! (3)
I believe the answer is:
nip
'move fast' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'if you want a pin-up' is the wordplay.
'pin' anagrams to 'NIP'.
However, I'm not sure how this is indicated.
Can you help me to learn more?
(Other definitions for nip that I've seen before include "Small drink of spirits" , "Pinch - tot" , "A small whisky" , "Feeling cold" , "small draught" .)