Of or pertaining to the root; proceeding directly from the root.
Hence: Of or pertaining to the root or origin; reaching to the center, to the foundation, to the ultimate sources, to the principles, or the like; original; fundamental; thorough-going; unsparing; extreme; as, radical evils; radical reform; a radical party.
Belonging to, or proceeding from, the root of a plant; as, radical tubers or hairs.
Proceeding from a rootlike stem, or one which does not rise above the ground; as, the radical leaves of the dandelion and the sidesaddle flower.
Relating, or belonging, to the root, or ultimate source of derivation; as, a radical verbal form.
Of or pertaining to a radix or root; as, a radical quantity; a radical sign. See below.
A primitive word; a radix, root, or simple, underived, uncompounded word; an etymon.
A primitive letter; a letter that belongs to the radix.
One who advocates radical changes in government or social institutions, especially such changes as are intended to level class inequalities; -- opposed to conservative.
A characteristic, essential, and fundamental constituent of any compound; hence, sometimes, an atom.
Specifically, a group of two or more atoms, not completely saturated, which are so linked that their union implies certain properties, and are conveniently regarded as playing the part of a single atom; a residue; -- called also a compound radical. Cf. Residue.
When you are right you cannot be too radical; when you are wrong, you cannot be too conservative. Martin Luther King, Jr.
If you have always believed that everyone should play by the same rules and be judged by the same standards, that would have gotten you labeled a radical 60 years ago, a liberal 30 years ago and a racist today. Thomas Sowell
I never dared to be radical when young for fear it would make me conservative when old. Robert Frost
Only crime and the criminal, it is true, confront us with the perplexity of radical evil; but only the hypocrite is really rotten to the core. Hannah Arendt
To be radical, an empiricism must neither admit into its constructions any element that is not directly experienced, nor exclude from them any element that is directly experienced. William James