reprehensible - Describing behavior, actions, or conduct that is morally wrong and worthy of disapproval or condemnation.
Though he told people not to repeat it, it was reprehensible for him to spread rumors about his colleague, knowing it would damage her reputation.
preposterous - Contrary to reason or common sense; utterly absurd or ridiculous.
When Sandy's stock broker called and suggested that he sell half his stocks because he felt the market was overvalued, Sandy thought the idea was preposterous - but it turned out that his stock broker was right.
