Arising from or going to a root or source; basic: proposed a radical solution to the problem.
Departing markedly from the usual or customary; extreme: radical opinions on education.
Favoring or effecting fundamental or revolutionary changes in current practices, conditions, or institutions: radical political views.
Linguistics Of or being a root: a radical form.
Botany Arising from the root or its crown: radical leaves.
Slang Excellent; wonderful.
One who advocates fundamental or revolutionary changes in current practices, conditions, or institutions: radicals seeking to overthrow the social order.
Mathematics The root of a quantity as indicated by the radical sign.
An atom or a group of atoms with at least one unpaired electron.