Familiar with outside bar I trashed (4,2)
I believe the answer is:
used to
'familiar with' is the definition.
(I've seen this before)
'outside bar i trashed' is the wordplay.
'bar' is a deletion indicator ('bar' can mean 'except' or 'apart from').
'trashed' is an anagram indicator.
'outside' with 'i' removed is 'outsde'.
'outsde' is an anagram of 'USED TO'.
(Other definitions for used to that I've seen before include "Did at times in the past" , "Not unfamiliar with" , "Accustomed or inured" , "Was in the habit" , "Familiar with" .)