Glare - then behold small swords! (4,7)
I believe the answer is:
look daggers
'glare' is the definition.
(I've seen this before)
'then behold small swords' is the wordplay.
'then' is a charade indicator (letters next to each other).
'behold' becomes 'look' (I've seen this before).
'small swords' becomes 'daggers' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'look' put next to 'daggers' is 'LOOK DAGGERS'.
Can you help me to learn more?
(Other definitions for look daggers that I've seen before include "Glare" , "appear furious" .)