His behavior was thought to be an anomaly.

His behavior is completely abnormal.

He was punished for his disobedience to the rules.

This liquid is nonfreezing, so it does not freeze even in winter.

His feelings are in the realm of the unknowable.

His actions are uncertain, and I have no idea what he's thinking.

He seemed unhappy about something.

The new product is unpopular, and sales are declining.

The new product was unpopular, and sales fell.

He had a hard time accepting his bad grade.