expostulate about (someone or something
To engage in a passionate discussion or argument about someone or something. Oh boy, steer clear of Uncle Ed if he's expostulating about politics again.
expostulate about someone or somethingand expostulate on someone or something
to comment or argue intensely about someone or something. He always seems to be expostulating on something. Why can't he simply say "Yes" or "No"? Sam is expostulating on Bill's many shortcomings again.
See also: expostulate