Even monster lost footing (3)
I believe the answer is:
yet
'even' is the definition.
(I know that even can be written as yet)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for yet that I've seen before include "'But, however (3)'" , "Still; however" , "Up to the present time" , "Still, so far" , "To this time, nevertheless" .)