pyromaniac
From Longman Dictionary of Contemporary EnglishRelated topics: Psychology, psychiatrypyromaniacpy‧ro‧ma‧ni‧ac /ˌpaɪrəʊˈmeɪniæk $ -rə-/ noun [countable] medicalMP someone who suffers from a mental illness that gives them a strong desire to start fires —pyromania noun [uncountable]Examples from the Corpuspyromaniac• A pyromaniac doesn't throw away the last three matches.