The word 'stupefying' originates from the Latin verb stupere, meaning "to be stunned or benumbed," which itself may trace back to a Proto-Indo-European root meaning "to push, strike." Combined with the causative suffix -fy (from Latin -facere, "to make"), the verb 'stupefy' literally means "to make numb or stunned." The present participle form -ing transforms this action into an adjective describing something that has this overwhelming, mind-numbing effect. Thus, the modern abstract meaning of causing extreme astonishment or mental dullness directly follows the literal logic of rendering someone in a state of stupefaction.

Structure: stupe (numb) + fy (make) + ing (adjective suffix) - stupe: From Latin stupere (to be stunned, numb), functioning as the core root conveying a state of insensibility. - fy: From Latin -ficare, via Old French -fier, a verb-forming suffix meaning "to make" or "to cause to become". - ing: From Old English -ende, a suffix used to form present participles which can function as adjectives.