Home -- and not home, somehow (2,1,3)
I believe the answer is:
in a way
'somehow' is the definition.
(I've seen this before)
'home and not home' is the wordplay.
'home' becomes 'in' ('he's home' can mean 'he's in').
'and' says to put letters next to each other.
'not home' becomes 'away' ('away' is the opposite to 'home').
'in'+'away'='IN A WAY'
(Other definitions for in a way that I've seen before include "somehow" , "To some degree" , "In some respects, to a limited extent" , "Sort of, in some respects" , "To a certain extent" .)