Leading endlessly astray with negation (6)
I believe the answer is:
denial
'negation' is the definition.
(I've seen this in another clue)
'leading endlessly astray' is the wordplay.
'endlessly' means to remove the last letter.
'astray' is an anagram indicator.
'leading' with its final letter taken off is 'leadin'.
'leadin' is an anagram of 'DENIAL'.
'with' acts as a link.
(Other definitions for denial that I've seen before include "Saying it isn't so" , "Nailed (anag.)" , "Negation" , "Refusal, abnegation" , "Rejection or refusal" .)