Blessed state of vehicle caught in squally rain (7)
I believe the answer is:
nirvana
'blessed state' is the definition.
(blissful state in Buddhism)
'vehicle caught in squally rain' is the wordplay.
'vehicle' becomes 'van' (van is a kind of vehicle).
'caught in' is an insertion indicator.
'squally' indicates anagramming the letters (squally can mean stormy or windy).
'rain' anagrammed gives 'nira'.
'van' placed inside 'nira' is 'NIRVANA'.
'of' acts as a link.
(Other definitions for nirvana that I've seen before include "State of perfect happiness" , "Iran van (anag) - blissful state!" , "Buddhist 23" , "Eastern place or state of bliss" , "Kurt Cobain's grunge band" .)