Nabber's cry (6)
I believe the answer is:
gotcha
'nabber's cry' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for gotcha that I've seen before include "You've been caught" , "I have found you" , "I've trapped you!" , "You're caught - I understand you" , "claim to have made conquest?" .)