theorize vs theorise

theorize and theorise both are verbs.

Word	Noun	Adjective	Verb	Adverb
theorize	No	No	Yes	No
theorise	No	No	Yes	No

As verbs, theorize and theorise are synonyms defined as:

theorize and theorise: to believe especially on uncertain or tentative grounds

Other synonyms of theorize include conjecture, hypothecate, hypothesise, hypothesize, speculate, suppose.

theorize (verb)	theorise (verb)
to believe especially on uncertain or tentative grounds	to believe especially on uncertain or tentative grounds
form or construct theories
construct a theory about