Unbosom (7)
I believe the answer is:
confide
'unbosom' is the definition.
(I know that confide is a is a kind of of unbosom)
This is all the clue.
(Other definitions for confide that I've seen before include "Tell secret as to friend - mum's the word" , "Trust wholly (in person)" , "Impart secrets to someone" , "Tell secret or entrust to" .)