A German boy without a girl (8)
I believe the answer is:
bavarian
'a german' is the definition.
(I know that Bavarian is a type of german)
'boy without a girl' is the wordplay.
'boy' becomes 'brian' ().
'without' indicates putting letters inside ('without' can be similar in meaning to 'outside').
'a girl' becomes 'ava'.
'brian' going around 'ava' is 'BAVARIAN'.
(Other definitions for bavarian that I've seen before include "from the Continent" , "Southern German" .)