Nick is apt to support Mike (14)
I believe the answer is:
misappropriate
'nick' is the definition.
(I've seen this before)
'apt to support mike' is the wordplay.
'apt' becomes 'appropriate' (synonyms).
'to' means one lot of letters go next to another (I've seen this in other clues).
'support mike' becomes 'mis' (I can't justify this - if you can you should give a lot more credence to this answer).
'appropriate' after 'mis' is 'MISAPPROPRIATE'.
'is' acts as a link.
Can you help me to learn more?
(Other definitions for misappropriate that I've seen before include "pocket" , "Lift" , "Unfairly take for one's own use" , "embezzle" , "Wrongly assume" .)