portmanteau formed from trump + petard (in the sense of Shakespeare's "hoist with his own petard')
def: a linguistic "reveal" of pathological liars (like Trump), wherein a statement is "exploded" (revealed to be completely devoid of veracity) by an immediately following conflicting/contradictory statement.
An ignorant blowhard who makes a lot of noise, blindly and militantly, defending Donald Trump... Especially fond of Trolling on social media. Also known as a "Trump Troll" or "Trumpkin".