Altogether part of everybody (2,3)
I believe the answer is:
in all
'altogether' is the definition.
(synonyms)
'part of everybody' is the wordplay.
'part of' becomes 'in' (being in something means being part of it).
'everybody' becomes 'all' (all people).
'in'+'all'='IN ALL'
(Other definitions for in all that I've seen before include "Everything considered" , "Taking everything into account" , "Completely" , "With everything counted" , "Taken as a whole" .)