mass murderer mass murder • mass noun · · · Info · Definitions · Characters · · mass murderer · · Text Common · · Latin · · Scripts 13 · · Length 4 · · Syllables Definitions · · · (noun) a person who is responsible for the deaths of many victims in a single incident. Synonyms: mass murderer. · · Noun Definition 1 Characters · · space U+0020 a latin small letter a U+0061 d latin small letter d U+0064 e latin small letter e U+0065 m latin small letter m U+006D r latin small letter r U+0072 s latin small letter s U+0073 u latin small letter u U+0075