Austrian novice of slender build (8)
I believe the answer is:
tyrolean
'austrian' is the definition.
(someone from Tyrol in Austria)
'novice of slender build' is the wordplay.
'novice' becomes 'tyro' (term for a beginner).
'of slender build' becomes 'lean' (lean can mean slender or skinny).
'tyro'+'lean'='TYROLEAN'
(Other definitions for tyrolean that I've seen before include "Austrian" , "native of Innsbruck?" , "from mountainous part of Europe" , "European" , "Native of picturesque mountainous region of western Austria" .)