Put off by the German and French inside (5)
I believe the answer is:
deter
'put off' is the definition.
(thesaurus)
'the german and french inside' is the wordplay.
'the german' becomes 'der' ('the' in German).
'and french' becomes 'et' ('and' in the French language).
'inside' is an insertion indicator.
'der' enclosing 'et' is 'DETER'.
'by' acts as a link.
(Other definitions for deter that I've seen before include "Dishearten" , "stop" , "Cause not to do something" , "Discourage or impede" , "Inhibit" .)