Current quote backing the bitter (6)
I believe the answer is:
acetic
'bitter' is the definition.
Although both the answer and definition are adjectives, I cannot see how they can define each other.
'current quote backing' is the wordplay.
'current' becomes 'ac' (alternating current).
'quote' becomes 'cite' (synonyms).
'backing' shows that the letters should be reversed in order.
'cite' written backwards gives 'etic'.
'ac'+'etic'='ACETIC'
'the' is the link.
Can you help me to learn more?
(Other definitions for acetic that I've seen before include "Vinegar-like" , "really sour" , "Saucy'" , "tart" , "Colourless pungent acid" .)