Under stress, uncovered weapon? (3)
I believe the answer is:
axe
'weapon?' is the definition.
(axe is a type of weapon)
'under stress uncovered' is the wordplay.
'under stress' becomes 'taxed' (I've seen this in another clue).
'uncovered' means to look at the middle letters.
The middle of 'taxed' is 'AXE'.
(Other definitions for axe that I've seen before include "can bring down plane" , "Cutter" , "Dispense with" , "Guitar" , "Fraternize" .)