coincidence theorist UK /kəʊ̯ˈɪnsɪdəns ˌθɪ.əɹɪst/US /koʊ̯ˈɪnsədəns ˌθiː.əɹɪst/ noun1 •(disapproving) Someone who rejects the claims of conspiracy theories, believing that any observations or occurrences are just coincidences. formscoincidence theorists