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.
implausible
The definition for implausible is "Unbelievable." Used in a sentence: Claudia's implausible excuse failed to convince her teacher.
moderate
The definition for moderate is "Tending toward the average." Used in a sentence: The best–selling writer was disappointed; his new novel was only a moderate success.
onset
The definition for onset is "Beginning." Used in a sentence: Crocuses bloom at the onset of spring, sometimes even before the snow melts.
unscrupulous
The definition for unscrupulous is "Lacking principles." Used in a sentence: The unscrupulous salesman was fired for lying to his customers.