Cut when shifting ale crate (8)
I believe the answer is:
lacerate
'cut' is the definition.
(I've seen this before)
'shifting ale crate' is the wordplay.
'shifting' indicates anagramming the letters.
'ale'+'crate'='alecrate'
'alecrate' with letters rearranged gives 'LACERATE'.
'when' acts as a link.
(Other definitions for lacerate that I've seen before include "Cut, leaving jagged edges" , "Tear or gash roughly" , "Tear roughly, cut jaggedly" , "Slash" , "Clare ate (anag)" .)