Secret initially suppressed in public (5)
I believe the answer is:
overt
'in public' is the definition.
(I've seen this before)
'secret initially suppressed' is the wordplay.
'secret' becomes 'covert' ('covert' can be similar in meaning to 'secret').
'initially suppressed' means to remove the first letter.
'covert' with its initial letter removed is 'OVERT'.
(Other definitions for overt that I've seen before include "Plain to see - manifest" , "Open, not 1 across" , "Not locked away" , "Patent, evident" , "Done in an obvious way" .)