Knights, perhaps, caught defecting Nazi soldiers (8)
I believe the answer is:
chessmen
'knights perhaps' is the definition.
(knight is a kind of chessman)
'caught defecting nazi soldiers' is the wordplay.
'caught' becomes 'c' (cricket abbreviation).
'defecting nazi' becomes 'Hess' (Nazi politician Rudolf Hess).
'soldiers' becomes 'men' (men can mean a group of soldiers).
'c'+'hess'+'men'='CHESSMEN'
(Other definitions for chessmen that I've seen before include "Pawns, knights, bishops etc - males only" , "Pawns, queens, rooks etc" , "Bishops and knights, say" , "'Bishops, pawns etc (8)'" , "Knights, rooks, pawns etc collectively - even the queen" .)