See person holding back fencing sword (4)
I believe the answer is:
epee
'fencing sword' is the definition.
(epee is a kind of fencing sword)
'see person holding back' is the wordplay.
'holding' indicates the answer is hidden within the clue.
'back' says the letters should be written backwards.
'eepe' can be found hidden inside 'see person'.
'eepe' reversed gives 'EPEE'.
(Other definitions for epee that I've seen before include "Fighting blade" , "Fencing weapon" , "Type of sword" , "Duelling weapon" , "there's a point to it" .)