Crossword Genius

Longs to inhabit street that's most exclusive (8)

Ross

I believe the answer is:

swishest

'most exclusive' is the definition.

'longs to inhabit street' is the wordplay.
'longs' becomes 'wishes'.
'to inhabit' is an insertion indicator.
'street' becomes 'st'.
'wishes' going within 'st' is 'SWISHEST'.

'that's' is the link.

(Another definition for swishest that I've seen is " Most elegant".)

I've seen this clue in The Guardian.
Want a hint initially instead of a full solution? Install my app