MALATHION Meaning of MALATHION in English [ ˌmalə'θʌɪən ]■ noun a synthetic organophosphorus compound used as an insecticide.Origin1950s: from (diethyl) mal(eate) (see maleic acid ) + thio- + -on . Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004