Perfect state of Irish victor housed by granny (7)
I believe the answer is:
nirvana
'perfect state' is the definition.
(I've seen this before)
'irish victor housed by granny' is the wordplay.
'irish' becomes 'IR' (abbreviation).
'victor' becomes 'V' (phonetic alphabet: alpha, bravo, charlie etc.).
'housed by' indicates putting letters inside.
'granny' becomes 'nana' (both can mean a grandmother).
'ir'+'v'='irv'
'irv' inserted within 'nana' is 'NIRVANA'.
'of' is the link.
(Other definitions for nirvana that I've seen before include "State of perfect happiness" , "Buddhist blessed extinction" , "Transcendent state of Buddhists" , "State of pure happiness" , "State finally acquired" .)