One who possesses a lower rapport with the bro community than he considers himself to possess.
The etymology is traced from the Sudra caste of Vedic canon; a subro is considered inferior to bros of a finer variety.

When you eat dirt for the first time and leave your family to build a shack in the woods

A club in which the only members are Chelsea, Ian, vampires and werewolves. This club consists of sitting in a circle, naked, eating pie and play on Nintendo DS's, after which it involves plotting against Bella Swan. Also, naked pie fights.

Origin: taken from the word 'super' and the word pro'. A common misspelling is 'supro', but that's just silly.