obsessionalEnglishOxford New American Dictionaryobsessional /əbˈseSH(ə)n(ə)l, , əbˈsɛʃ(ə)n(ə)l , äbˈseSH(ə)n(ə)l, ɑbˈsɛʃ(ə)n(ə)l / ▸ adjective characteristic of or affected by an obsession: people with chronic obsessional behavior a single-minded or even obsessional leader. – DERIVATIVES obsessionally /əbˈseSH(ə)nəlē, , əbˈsɛʃ(ə)nəli , äbˈseSH(ə)nəlē, ɑbˈsɛʃ(ə)nəli / adverb,obsessionalism