Goodness! Get six right before Tuesday! (6)
I believe the answer is:
virtue
'goodness' is the definition.
(virtue is a kind of goodness)
'six right before tuesday' is the wordplay.
'six' becomes 'VI' (Roman numerals).
'right' becomes 'r' (common abbreviation).
'before' is a charade indicator (letters next to each other).
'tuesday' becomes 'tue' (short for Tuesday).
'vi'+'r'+'tue'='VIRTUE'
'get' is the link.
(Other definitions for virtue that I've seen before include "High-mindedness" , "Moral goodness" , "Maybe hope" , "Patience, for example?" , "''....is it's own reward'' (6)" .)