Prefix

Prefix	Meaning	Examples
counter-	opposition, opposite direction	counter-attack, counteract
extra-	outside, beyond	extracurricular
infra-	below	infrared, infrastructure
peri-	round, about	perimeter
contra-	against, opposite	contraceptive
hyper-	beyond, more than, more than normal	hypersonic, hyperactive
post-	after in time or order	postpone
pre-	before in time, place, order or importance	pre-adolescent, prelude, precondition
re-	again	repaint, reappraise, reawake
semi-	half, partly	semicircle, semi-conscious