adversary
The definition for adversary is "One who opposes or resists." Used in a sentence: Franklin hoped to defeat his adversary in the afternoon's tennis match.
augment
The definition for augment is "To make greater." Used in a sentence: Wanda read the dictionary every night to augment her vocabulary.
conduit
The definition for conduit is "Means for transmitting or distributing." Used in a sentence: Jason, a notorious gossip, was a conduit for information about his friends.
induce
The definition for induce is "To influence or cause." Used in a sentence: The loud blast of the cannon induced an avalanche.
retroactive
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.