When caught, children surrender (4)
I believe the answer is:
cede
'surrender' is the definition.
(synonyms)
'when caught children' is the wordplay.
'when caught' shows a homophone (sound like).
'children' becomes 'seed' (seed can mean one's offspring).
'seed' is a homophone of 'CEDE'.
(Other definitions for cede that I've seen before include "Yield or give up to another" , "Relinquish control of" , "21 across" , "Yield, give way" , "Surrender or relinquish possession" .)