Locks up unusually sour delights (8)
I believe the answer is:
enamours
'delights' is the definition.
(to enamour is to delight or please)
'locks up unusually sour' is the wordplay.
'locks' becomes 'mane' (I've seen this in other clues).
'up' is a reversal indicator (in down clue: letters go upwards).
'unusually' indicates an anagram.
'mane' written backwards gives 'enam'.
'sour' with letters rearranged gives 'ours'.
'enam'+'ours'='ENAMOURS'
(Other definitions for enamours that I've seen before include "Sue Norma, who causes one to love" , "Charms" , "Captures heart with our names" .)