Pass by failing to fail (8)
I believe the answer is:
collapse
'fail' is the definition.
(I've seen this before)
'pass by failing' is the wordplay.
'pass' becomes 'col' (col is a term for a mountain pass).
'by' means one lot of letters go next to another.
'failing' becomes 'lapse' (I've seen this before).
'col'+'lapse'='COLLAPSE'
'to' is the link.
(Other definitions for collapse that I've seen before include "Fall down or lose strength suddenly" , "Slump" , "Give way, fail suddenly" , "Fall or disintergrate" , "Disintegration" .)