adj. 25B6; adjective DYING OUT, on the decline, declining, waning, on the wane, disappearing, past its prime, ageing, moribund, on its last legs, out of date, outdated, old-fashioned, outmoded; informal on the way out, past it.
OBSOLESCENT
Meaning of OBSOLESCENT in English
Concise Oxford thesaurus English vocabulary. Краткий оксфордский словарь английского языка тезаурус. 2012