i Register
In some senses, dizzard is marked as obsolete. Watch for register when choosing this word.
noun
A jester or fool.
An idiot.
Lactantius, in his book of Wisdom, proves them to be dizzards, fools, asses, madmen, so full of absurd and ridiculous tenets and brain-sick positions, that to his thinking never any old woman doted worse.
"You're a dizzard!" I retorted. "And a noodle and a jolt-head;[…]you're a Hatter!" I shrieked the last epithet.