l-de-sac [noun] [C] - a short road which is blocked off at one endWe live in a cul-de-sac, so we don't get much traffic noise.(figurative) We have come to a cul-de-sac with our enquiries (= they are leading nowhere).
CU
Meaning of CU in English
Cambridge English vocab. Кембриджский английский словарь. 2012