Looked daggers at Gerald, possibly (6)
I believe the answer is:
glared
'looked daggers' is the definition.
(I've seen this in another clue)
'gerald possibly' is the wordplay.
'possibly' indicates anagramming the letters.
'gerald' with letters rearranged gives 'GLARED'.
'at' is the link.
(Other definitions for glared that I've seen before include "Was too bright" , "Lowered" , "Looked angrily" , "Glowered" , "Stared fiercely" .)