not concealed (11)
(Other definitions for exposed that I've seen before include "Deprived of protection" , "Brought to light" , "in the nude" , "Made public" , "Like a dummy" .)
(Another definition for undisguised that I've seen is " Manifest".)
'not concealed' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for overt that I've seen before include "Plain to see - manifest" , "Open and undisguised" , "Open,up front" , "Open and candid" , "Plain and obvious" .)