Occasionally thank one German for house (4,2)
I believe the answer is:
take in
'house' is the definition.
(taking in is a kind of housing)
'occasionally thank one german' is the wordplay.
'occasionally' indicates alternate letters.
'one german' becomes 'ein' ('one' in German).
The alternate letters of 'thank' are 'tak'.
'tak'+'ein'='TAKE-IN'
'for' is the link.
(Other definitions for take in that I've seen before include "Enclose; deceive" , "Provide with shelter, or delude" , "contract" , "Deceive (someone)" , "Fraud" .)