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 intricate is "Having complex and interrelated parts." Used in a sentence: The intricate poem baffled most readers with its numerous obscure metaphors.

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.

The definition for ramble is "To wander, physically or in language." Used in a sentence: Professor Tan rambled during his lectures, frequently straying from the subject.

The definition for retroactive is "effective as of a prior time or condition." Used in a sentence: The retroactive law made even past infractions punishable.