Independent 'at home' almost split posh top celebs (13)
I believe the answer is:
individualist
'independent' is the definition.
(thesaurus)
'home almost split posh top celebs' is the wordplay.
'home' becomes 'in' ('he's home' can mean 'he's in').
'almost' means to remove the last letter (most of the word but not all of it).
'split' becomes 'divide' ('divide' can be a synonym of 'split').
'posh' becomes 'u' (abbreviation for upper-class - opposite to non-u).
'top celebs' becomes 'alist' (A-list**).
'divide' with its final letter taken away is 'divid'.
'in'+'divid'+'u'+'alist'='INDIVIDUALIST'
'at' is the link.
(Other definitions for individualist that I've seen before include "Self-centred person" , "Maverick" , "One with an independent outlook" , "One showing independence" .)