/ Dictionary / Index G guanethidine: Meaning and Definition of Find definitions for: guan•eth•i•dine Pronunciation: (gwon-eth'i-dēn"), [key] — n. Pharm. a potent adrenergic neuron blocking agent, CHN, used in the treatment of hypertension. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Guandong Guangdong Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language