specious

Forty years ago I was not yet thirty, and my father still held to the hope that I would come to my senses, abandon the practice of journalism, and follow a career in one of the Wall Street money trades. As a young man during the Great Depression he had labored briefly as a city-room reporter for William Randolph Hearst's San Francisco Examiner, and he knew that the game was poorly paid and usually rigged, more often than not a matter of converting specious rumor into dubious fact. —Lewis H. Lapham, Harper's, February 2004

One must always guard the interests of one's constituency in the public forum even when its claims are weak or perhaps specious, lest one's opponents steal the march in the never-ending battle for resources or public support. —Robert Jackall et al., Image Makers, 2000

By and large, they made these changes with specious explanations or no explanation at all. Today, when curricula list rhetoric as a subject, it usually means simply the study of how to write effectively. —Walter J. Ong, Orality and Literacy, (1982) 2002

He justified his actions with specious reasoning.

a specious argument that really does not stand up under close examination