chlorambucilPronunciation: /klɔːˈrambjʊsɪl/Definition of chlorambucil noun [mass noun] Medicine a cytotoxic drug used in the treatment of cancer. Origin: 1950s: from chlor(oethyl)am(inophenyl)bu(tyric acid), the systematic name, + -cilchlorambucil in other Oxford dictionaries Definition of chlorambucil in the US English dictionary