duplicity
The definition for duplicity is "Deceptive thought, speech, or action." Used in a sentence: The life of an undercover detective is filed with necessary duplicity.
indecorous
The definition for indecorous is "In bad taste." Used in a sentence: My parents banned Chad from our house because of his indecorous behavior at dinner.
manifest
The definition for manifest is "Obvious." Used in a sentence: James finally made his affection manifest when he handed Jessica a red rose.
negate
The definition for negate is "To make invalid." Used in a sentence: Paula negated Tiffany's argument by proving that her main premise was false.
precept
The definition for precept is "A general rule of action." Used in a sentence: All the students know Mrs. Brown's strict precept; no talking in class.