Of or pertaining to the root; proceeding directly from the root.
- 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.
- Linguistics See root1.