Court nails suspect without hearing (10)
I believe the answer is:
ultrasonic
'without hearing' is the definition.
'court nails suspect' is the wordplay.
'suspect' indicates anagramming the letters.
'court'+'nails'='courtnails'
'courtnails' with letters rearranged gives 'ULTRASONIC'.
(Other definitions for ultrasonic that I've seen before include "Higher than can be heard" , "Of high frequency" , "Involving sound waves beyond human hearing" , "Above the limit of human hearing" .)