Walk casually in street — go round and round (6)
I believe the answer is:
stroll
'walk casually' is the definition.
(to stroll is to walk casually or leisurely)
'street go round and round' is the wordplay.
'street' becomes 'st' (abbreviation).
'go round and round' becomes 'roll' (I've seen this in another clue).
'st'+'roll'='STROLL'
'in' is the link.
(Other definitions for stroll that I've seen before include "A casual or leisurely walk" , "swan" , "cinch" , "gentle pace" , "A casual, relaxing walk" .)