D defs.my
Entry 1 sense Webster, 1913

Theorize

/thē'-ẽr-īzˌ/ · The·o·rize · IPA /ˈθɪɹ.aɪz/
01 v. i. To form a theory or theories; to form opinions solely by theory; to speculate.
imp. & p. p. Theorized; p. pr. & vb. n. Theorizing
  1. 1.
    To form a theory or theories; to form opinions solely by theory; to speculate.