illuminate
The definition for illuminate is "To make clear." Used in a sentence: Her excellent lecture illuminated the complicated subject of nuclear physics.
interminable
The definition for interminable is "Never ending, or seemingly endless." Used in a sentence: The impatient Zoe found the longwinded lecture interminable.
opportune
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.
pallid
The definition for pallid is "Lacking color." Used in a sentence: The nurse was worried by the patient's pallid face and shallow breathing.
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.