Happiness in German shelter (4)
I believe the answer is:
glee
'happiness' is the definition.
(glee is a kind of happiness)
'german shelter' is the wordplay.
'german' becomes 'g' (abbreviation).
'shelter' becomes 'lee' (I've seen this before).
'g'+'lee'='GLEE'
'in' acts as a link.
(Other definitions for glee that I've seen before include "Type of club" , "Lively or triumphant joy" , "Unholy delight" , "Part song for men" , "Unholy mirth or triumphant joy" .)