Expressing blissful happiness (8)
I believe the answer is:
beatific
'expressing blissful happiness' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for beatific that I've seen before include "Feeling or expressing blissful happiness" , "Befit CIA to be showing great happiness" , "supremely happy" , "Showing great happiness, perhaps a smile" , "Joyful" .)