She's knocking drink back at "The Galloping Nag" (6)
I believe the answer is:
angela
'she's' is the definition.
(I've seen this before)
'knocking drink back at the galloping nag' is the wordplay.
'knocking' says the letters should be written backwards.
'drink back' becomes 'ale' (type of beer. I am not sure about the 'back' bit.).
'at' is a charade indicator (letters next to each other) (I've seen this in other clues).
'the galloping' indicates an anagram (I've seen this in other clues).
'ale' in reverse letter order is 'ela'.
'nag' with letters rearranged gives 'ang'.
'ela' after 'ang' is 'ANGELA'.
Can you help me to learn more?
(Other definitions for angela that I've seen before include ". . . Lansbury (actress)" , "- Carter, English writer" , "Girl's name" , "Frau Merkel" , "woman" .)