Disregard past appearance (8)
I believe the answer is:
overlook
'disregard' is the definition.
(thesaurus)
'past appearance' is the wordplay.
'past' becomes 'over' (I've seen this before).
'appearance' becomes 'look' (look is a kind of appearance**).
'over'+'look'='OVERLOOK'
(Other definitions for overlook that I've seen before include "Ignore or fail to see" , "Fail to observe or consider" , "Keep an eye on" , "excuse" , "Ignore a fault or have a view from above" .)