It's best to notice patterns in the way that people respond to you to tell if they are truly being deceitful.
Option One used deceitful tactics to trick customers.
The early difficulties of Elizabeth's reign secured him a deceitful peace on that side for a time.
She felt deceitful pumping Mrs. Marsh for information about Brandon's plans, but it was the perfect opportunity.
In Homer he is one of the best and bravest of the heroes, and the favourite of Athena, whereas in later legend he is cowardly and deceitful.
He promoted navigation and commerce, but was avaricious and deceitful.
But if I'm supposed to avoid the subject, don't act like I'm in the middle of some deceitful act when I try.