Enemy, O my, has kidnapped crack recruit (6)
I believe the answer is:
engage
'recruit' is the definition.
(I've seen this before)
'enemy o my has kidnapped crack' is the wordplay.
I cannot quite see how this works, but
'crack' could be 'gag' (both can mean a joke) and 'gag' is found in the answer.
The remaining letters 'ene' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for engage that I've seen before include "Take on, hire" , "Mesh" , "Take on (eg for work, in battle)" , "Take someone on as a worker" , "Employ or take on" .)