Cripple Mike and Mark (4)
I believe the answer is:
maim
'cripple' is the definition.
(I've seen this before)
'mike and mark' is the wordplay.
'mike' becomes 'M' (phonetic alphabet: alpha, bravo, charlie etc.).
'and' says to put letters next to each other.
'mark' becomes 'mai' (I can't justify this - if you can you should give a lot more credence to this answer).
'm' put after 'mai' is 'MAIM'.
Can you help me to learn more?
(Other definitions for maim that I've seen before include "Cripple, mutilate" , "Wound or injure, disable" , "Injure or harm severely" , "'Disable, mutilate (4)'" , "Wound and cripple" .)