conspiratorialist
/kənˌspɪrəˈtɔːrɪəlɪst/ /ˌkɒnspɪrəˈtɔːrɪəlɪst/originally US
noun
A person who believes in or promotes conspiracy theories, a conspiracy theorist.
adjective
Of or relating to conspiratorialists or to conspiracy theories.
Origin
1960s. From conspiratorial + -ist. Compare earlier conspiratorialism.