Gin rates poorly, and most bitter (8)
I believe the answer is:
angriest
'most bitter' is the definition.
('angry' can be similar in meaning to 'bitter')
'gin rates poorly' is the wordplay.
'poorly' indicates anagramming the letters.
'gin'+'rates'='ginrates'
'ginrates' with letters rearranged gives 'ANGRIEST'.
'and' acts as a link.
(Other definitions for angriest that I've seen before include "Extremely mad" , "Most annoyed or hostile" , "Most irate and furious" , "Most wrathful" , "Most characteristic of 1950s young men" .)