diatribolical 

Crystal clear speech or rhetoric that is diabolical or evil in nature.

Hitler's diatribolical speeches inspired hatred among his followers.

diatribolical by matatre February 16, 2013

Diarybolical 

A diabolically large amount of meetings in a calendar in any given time period.

Mr Smith's schedule next week is diarybolical.

Diarybolical by JodieCB February 22, 2023