Lose one's figure within a month (6)
I believe the answer is:
mislay
'lose' is the definition.
('mislay' can be a synonym of 'lose')
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for mislay that I've seen before include "Lose (something)" , "Set in wrong location" , "Put something aside and forget where" , "Lose track of" , "Put (something) where it can't be found" .)