The definition for appalling is "Inspiring dismay or disgust." Used in a sentence: Hector found his roommate's habit of leaving his dirty socks on the floor appalling.

The definition for belated is "Past the normal or proper time." Used in a sentence: Even though I forgot his birthday, I hoe my father accepts my belated card.

The definition for foil is "One that enhances or underscores by contrast." Used in a sentence: The sweet cookie was a perfect foil to the sour lemon sorbet.

The definition for opportune is "Suitable or convenient." Used in a sentence: Quan stepped onto the platform at the most opportune time, just as the train pulled in.

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.