Martin Luther King, Jr.âs father, Martin Luther King, Sr. was not only a registered Republican, but he publicly endorsed Richard M. Nixon (a Republican) for President.
The definition of diabolical is something devilish or cunning in an evil way. A devilish and cunning plan to take over the world is an example of a diabolical plan. also diÂ·aÂ·bolÂ·ic. adjective. 1  Of, concerning, or characteristic of the devil; satanic.  Appropriate to a devil, especially in degree of wickedness or cruelty.
Ironical is a variant of ironic. It has no definitions of its own. It was once more common than ironic (see the ngram at the bottom of this post), but ironic now prevails by an overwhelming margin. Still, because the suffix conventions in English are inconsistent, ironical will probably continue to appear. For example, metaphorical is preferred over metaphoric, academic and seismic are preferred over academical and seismical, and economic and economical are both legitimate words with different meanings.