Empty pub about noon (6)
I believe the answer is:
barren
'empty' is the definition.
(thesaurus)
'pub about noon' is the wordplay.
'pub' becomes 'bar' (I've seen this before).
'about' becomes 're' (regarding).
'noon' becomes 'n'.
'bar'+'re'+'n'='BARREN'
(Other definitions for barren that I've seen before include "Incapable of sustaining life" , "Unproductive, arid" , "Sterile" , "Arid, infertile" , "Unable to bear young" .)