Tuesday before Ash Wednesday (6)
I believe the answer is:
shrove
'tuesday before ash wednesday' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for shrove that I've seen before include "This Tuesday is immediately before Ash Wednesday" , "This Tuesday comes before Ash Wednesday" , "Heard confession" , "The Tuesday before Lent" , "... Tuesday precedes Ash Wednesday" .)