Hostile, a rhyme about Germany (7)
I believe the answer is:
adverse
'hostile' is the definition.
(thesaurus)
'a rhyme about germany' is the wordplay.
'rhyme' becomes 'verse' ('verse' can be a synonym of 'rhyme'**).
'about' means one lot of letters go next to another.
'germany' becomes 'd' (international vehicle registration code).
'verse' after 'd' is 'dverse'.
'a'+'dverse'='ADVERSE'
(Other definitions for adverse that I've seen before include "Inimical" , "Dire" , "Unfavourable or harmful, perhaps criticism" , "Inopportune" , "In an opposing direction" .)