Inhibit (5)
'inhibit' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for deter that I've seen before include "Discourage (someone from an action)" , "Frighten off; prevent" , "Warn off" , "Inhibit" , "Try to prevent" .)
(Other definitions for cramp that I've seen before include "Muscle spasm" , "Muscular spasm, very painful" , "Confine - muscular spasm" , "Painful muscular contraction" , "Sudden painful tightening of a muscle" .)