Embarrassed about mistake getting something fortified (6)
I believe the answer is:
sherry
'something fortified' is the definition.
(I know this)
'embarrassed about mistake' is the wordplay.
'embarrassed' becomes 'shy' (shy can mean reserved or embarrassed).
'about' is an insertion indicator.
'mistake' becomes 'err' (to err is to make a mistake or blunder).
'shy' placed around 'err' is 'SHERRY'.
'getting' is the link.
(Other definitions for sherry that I've seen before include "Alcoholic drink" , "Alcoholic appetiser associated with Jerez" , "Wine from Spain's Jerez region, drunk as an aperitif" , "Fortified wine as aperitif" , "Preprandial drink" .)