1. (

• speculate ,
• theorize ,
• theorise ,
• conjecture ,
• hypothesize ,
• hypothesise ,
• hypothecate ,
• suppose ,

) to believe especially on uncertain or tentative grounds; "Scientists supposed that large dinosaurs lived in swamps" ;

2. (

• theorize ,

) construct a theory about; "Galileo theorized the motion of the stars" ;

3. (

• theorize ,

) form or construct theories; "he thinks and theorizes all day" ;