Band in street slightly indecent? (6)
I believe the answer is:
stripe
'band' is the definition.
(synonyms)
'street slightly indecent?' is the wordplay.
'street' becomes 'st' (abbreviation).
'slightly indecent?' becomes 'ripe' (ripe can mean indecent or vulgar).
'st'+'ripe'='STRIPE'
'in' acts as a link.
(Other definitions for stripe that I've seen before include "Military rank indicator" , "Narrow band of colour" , "Thin band of colour" , "bar" , "Band of colour - 3 of rank" .)