catastrophic
The definition for catastrophic is "Relating to extreme misfortune." Used in a sentence: The effects of the massive hurricane were catastrophic.
flaunt
The definition for flaunt is "To display showily." Used in a sentence: Sheila, who could not resist bragging, flaunted the "A" marked on her test paper.
placebo
The definition for placebo is "An inactive substance used in medical testing." Used in a sentence: Tom, who had taken the placebo, found that his allergy symptoms did not go away.
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.
punctual
The definition for punctual is "On time." Used in a sentence: Ron was worried when the usually punctual Amanda was late for the show.