obsessive /əbˈsɛs.ɪv/adjective 3noun 1forms 3 adjective3 •Having one thought or pursuing one activity (an obsession) to the absolute or nearly absolute exclusion of all others.Hardcore fans' obsessive behavior may take over their lives. •Excessive, as results from obsession.A workaholic's obsessive zeal may lead to success or burnout. •Prone to cause obsession.The idea is too tempting, it's obsessive. noun1 •A person who is obsessed, who has an obsession. formsobsessives · more obsessive · most obsessive