Mark Smedley's Attitude To Life

Someone who regularly contradicts themself, and looks like an idiot (or, dare I say, a MORON) each time they do so.

see -> conspiracy theory

a moron who does oxy. see oxygenius

Two words that seemingly contradict each other when used together.

Two words with contradicting meanings used together.
Something that appears self-contradictory.

Two words in a sentence that contradict each other. Not necessarily opposites, however