At home, irate, developing apathy (7)
I believe the answer is:
inertia
'apathy' is the definition.
(I've seen this before)
'at home irate developing' is the wordplay.
'at home' becomes 'in' ('I'm in' can mean 'I'm at home').
'developing' indicates anagramming the letters (letters developed into a new form).
'irate' is an anagram of 'ertia'.
'in'+'ertia'='INERTIA'
(Other definitions for inertia that I've seen before include "Listlessness" , "Tendency to inactivity" , "Tendency to do nothing or to remain unchanged" , "Motionlessness" , "Immobility" .)