Row about German beast (5)
I believe the answer is:
tiger
'beast' is the definition.
(thesaurus)
'row about german' is the wordplay.
'row' becomes 'tier' (tier is a kind of row**).
'about' means one lot of letters goes inside another.
'german' becomes 'g' (abbreviation).
'tier' enclosing 'g' is 'TIGER'.
(Other definitions for tiger that I've seen before include "Asian animal" , "Large striped cat" , "Big cat of Asia" , "fierce animal" , "Large forest cat" .)