theorize in WordNet English dictionary

1. to believe especially on uncertain or tentative grounds
   "Scientists supposed that large dinosaurs lived in swamps"
   speculate  theorize  theorise  conjecture  hypothesize  hypothesise  hypothecate  suppose 
   
2. form or construct theories
   "he thinks and theorizes all day"
   theorize 
   
3. construct a theory about
   "Galileo theorized the motion of the stars"
   theorize