One dined outside with German ape (7)
I believe the answer is:
imitate
'ape' is the definition.
(synonyms)
'one dined outside with german' is the wordplay.
'one' becomes 'i' (Roman numeral).
'dined' becomes 'ate' (I've seen this in another clue).
'outside' indicates putting letters inside.
'with german' becomes 'mit' ('with' in German).
'i'+'ate'='iate'
'iate' placed around 'mit' is 'IMITATE'.
(Other definitions for imitate that I've seen before include "Mimic or follow as a model" , "Follow suit" , "Take as a model" , "Copy or mimic" , "Copy someone" .)