Emily Dickinson Lexicon

PRUDE, n. [Fr. prude, wise, discreet, sober, formal, precise; D. preutsch, prudish, and proud; G. spröde, a prude, and shy, cold, reserved, coy, demure, and applied to metals, brittle, friable; Dan. sprödig, eager, brittle, harsh, dry, rugged; W. pruz, (prudh,) prudent, discreet, serious, sad, sorrowful; Goth. frods, prudent; Gr. φραδη, prudence; Goth. frathi, mind, intellect; frathyan, to be wise, to understand. The Goth. frod signifies both wise, prudent, and broken; D. vroed, prudent. We see that prude, prudent, and proud are from the same root. The sense of brittle would indicate that these words belong to the same family with the Dan. bryder, to break; and the radical elements are the same. The Welsh pruz is from tending out or reaching, hence pryder, anxiety, a stretching of the mind. The sense of pride is probably from stretching, straitness, stiffness; and the sense of wise is derivative. Prudence is from the same root, implying care, a tension of mind.]

A woman of great reserve, coyness, affected stiffness of manners and scrupulous nicety. Less modest than the speech of prudes. – Swift.