hypothesize hypothesize /haɪˈpɑːθəˌsaɪz/

verb

1. () To believe especially on uncertain or tentative grounds  ( hypothecate , hypothesise [British] , theorise [British] , conjecture , hypothesize , speculate , suppose , theorize )
   to believe especially on uncertain or tentative grounds
    Scientists supposed that large dinosaurs lived in swamps
   Scientists supposed that large dinosaurs lived in swamps