Spice up endless shanty (6)
I believe the answer is:
season
'spice up' is the definition.
(I've seen this in another clue)
'endless shanty' is the wordplay.
'endless' means to remove the last letter.
'shanty' becomes 'sea song' (a shanty is a sea song).
'seasong' with its last letter removed is 'SEASON'.
(Other definitions for season that I've seen before include "' - - of mists ...' (Keats)" , "eg.Summer" , "Add flavouring" , "Eg, summer" , "One of four periods" .)