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 incidental is "minor.", the definition for drab is "Dull, monotonous.", and the definition for iridescent is "Having a lustrous or attractivve quality."

The definition for raucous is "Noisy, rowdy." Used in a sentence: Serena, who preferred quiet conversation, left the rancous party. The definition for augment is "to make greater.", the definition for appalling is "Inspiring dismay or disgust.", and the definition for preclude is "To rule out in advance."

The definition for periodic is "Occurring at regular intervals." Used in a sentence: The periodic innterruptions of the cuckoo clock prevented Li from concentrating. The definition for repentant is "feeling regret.", the definition for hedonism is "Belief that pleasure is the sole aim of life.", and the definition for trove is "Valuable collection."

The definition for combustion is "Act of burning." Used in a sentence: Campers must use fire with great caution to prevent combustion of the parched brush. The definition for brandish is "to shake or wave menacingly.", the definition for hedonism is "Belief that pleasure is the sole aim of life.", and the definition for trove is "Valuable collection."

The definition for straddle is "To favor opposing sides." Used in a sentence: Kia straddled the issue, not wanting to say whether James or Tara was right. The definition for cunning is "showing clever insight.", the definition for epitaph is "Brief statement honoring a dead person.", and the definition for periodic is "Occurring at regular intervals."