Rough diamonds in Parisian street (4)
I believe the answer is:
rude
'rough' is the definition.
(similar in meaning)
'diamonds in parisian street' is the wordplay.
'diamonds' becomes 'd' (abbreviation in bridge say).
'in' means one lot of letters goes inside another.
'parisian street' becomes 'rue' ('street' in French).
'd' placed inside 'rue' is 'RUDE'.
(Other definitions for rude that I've seen before include "Coarse, unpolished" , "Uncouth" , "Offensively impolite" , "Uncivilised" , "Impolite; unpolished" .)