Failure leads to guru expounding about pique (7)
I believe the answer is:
dudgeon
'pique' is the definition.
(I've seen this in another clue)
'failure leads to guru expounding about' is the wordplay.
'failure' becomes 'dud' (dud is a kind of failure).
'leads to' says to take the initial letters.
'about' becomes 'on' (as in a book 'on' a certain topic).
The initial letters of 'guru expounding' is 'ge'.
'dud'+'ge'+'on'='DUDGEON'
(Other definitions for dudgeon that I've seen before include "Feeling of intense indignation" , "Devil's Disciple" , "Deep resentment" , "feeling of resentment" , "Anger" .)