Run out short extension over German's house (7)
I believe the answer is:
exhaust
'run out' is the definition.
(thesaurus)
'extension over german's house' is the wordplay.
'extension' becomes 'ext' (abbreviation, as in a telephone extension).
'over' is an insertion indicator.
'german's house' becomes 'haus' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'ext' placed around 'haus' is 'EXHAUST'.
'short' acts as a link.
Can you help me to learn more?
(Other definitions for exhaust that I've seen before include "Burnt gases are discharged here" , "part of car - > tire?" , "lower part of estate?" , "Devitalize, drain of energy" , "Sap - piped emission" .)