Good German red backing drunkard into caves (7)
I believe the answer is:
grottos
'caves' is the definition.
(I've seen this before)
'good german red backing drunkard' is the wordplay.
'good german red' becomes 'grot' (I can't justify this - if you can you should believe this answer much more).
'backing' says the letters should be written backwards.
'drunkard' becomes 'sot' (synonyms).
'sot' reversed gives 'tos'.
'grot'+'tos'='GROTTOS'
'into' acts as a link.
Can you help me to learn more?
(Another definition for grottos that I've seen is " caves".)