At home, a sight? Possibly (2,1,5)
I believe the answer is:
in a sense
'possibly' is the definition.
Both the answer and definition are adverbs. Perhaps you can see a link between them that I don't see?
'at home a sight?' is the wordplay.
'at home' becomes 'in' (similar in meaning).
'sight?' becomes 'sense' (sighting is a kind of sensing).
'in'+'a'+'sense'='IN A SENSE'
Can you help me to learn more?
(Other definitions for in a sense that I've seen before include "According to one possible interpretation" , "After a fashion" , "To some extent" .)