VERITABLE means real, genuine, or authentic — truly what it is said to be. Its antonym is specious, which means appearing valid or genuine on the surface but actually false or misleading. 'Impetuous' means acting on impulse. 'Pernicious' means harmful. 'Inefficacious' means not producing the desired effect. Only 'specious' (false appearance of truth) directly opposes 'veritable' (genuine truth).