Drunk at the bar - man is astonishing (12)
I believe the answer is:
breathtaking
'astonishing' is the definition.
(thesaurus)
'drunk at the bar man' is the wordplay.
'drunk' indicates anagramming the letters.
'man' becomes 'king' (king is a kind of man**).
'at'+'the'+'bar'='atthebar'
'atthebar' anagrammed gives 'breathta'.
'breathta'+'king'='BREATHTAKING'
'is' is the link.
(Other definitions for breathtaking that I've seen before include "Moving" , "Astounding" , "way of getting air into the lungs" , "if one is not one is dead?" , "Causing astonishment" .)