fickle
The definition for fickle is "Lacking constancy, changeable." Used in a sentence: The fickle Senji had a new best friend every month.
illuminate
The definition for illuminate is "To make clear." Used in a sentence: Her excellent lecture illuminated the complicated subject of nuclear physics.
prudent
The definition for prudent is "Marked by wisdom, shrewd." Used in a sentence: Manny was happy she followed Greg's prudent advice to study, as the test was difficult.
raucous
The definition for raucous is "Noisy, rowdy." Used in a sentence: Serena, who preferred quiet conversation, left the rancous party.
surplus
The definition for surplus is "Excess." Used in a sentence: Trevor decided to freeze the surplus chili for next week's tailgate party.