Journal I binned contains excuse for failure (5)
I believe the answer is:
alibi
'excuse for failure' is the definition.
(I've seen this before)
'journal i binned contains' is the wordplay.
'contains' says the answer is hidden in the clue.
'ALIBI' is hidden in the letters of 'journal i binned'.
(Other definitions for alibi that I've seen before include "Defence in court" , "Lawyer's weapon, Latin for 'elsewhere'" , "Suspect's excuse" , "Defence against charge - was seen elsewhere" , "Evidence that the accused could not have been guilty" .)