Ludicrous is an adjective used to describe something so absurd that it provokes laughs and mockery. One synonym is ridiculous.
A San Diego stock adviser who is accused of bribing an F.B.I. agent to give him confidential government information may have had prior knowledge of the Sept. 11 attacks, a federal prosecutor said yesterday. But a judge disregarded that contention and the adviser’s lawyer called the allegation ludicrous. (NY Times)
Some attacks on health care reform are so ludicrous that you don’t think they need answering. A recent example invokes an evil plot to save money by knocking off the elderly. (Houston Chronicle)