Ignore idiot in empty pub yard (4,2)
I believe the answer is:
pass by
'ignore' is the definition.
(thesaurus)
'idiot in empty pub yard' is the wordplay.
'idiot' becomes 'ass' (I've seen this before**).
'in' indicates putting letters inside.
'empty' says to hollow out the word (remove centre letters).
'yard' becomes 'y'.
'pub' with its centre removed is 'pb'.
'ass' put inside 'pb' is 'passb'.
'passb'+'y'='PASS BY'
(Other definitions for pass by that I've seen before include "Leave on one side" , "Ignore, overlook" , "Go on and leave alone" , "''Cast a cold eye / On life, on death / Horseman ... ... (WB Yeats)" , "neglect" .)