2 definitions by It's true ask your mum

Hilliard

An event that is simple in nature but is fucked up catastrophically, completely and utterly unfathomable.

Tom was washing lettuce for his dinner and somehow managed to burn the house down, Fuck Tom what a Hilliard.

Making a decision with zero thought or regard of possible repercussions to yourself or others.

Tom was on patrol, a lowly tech walks across his area he sends his attack dog in to absolutely fucking destroy him! Fuck Tom what a bowman!