Despite the tense meeting, Mark couldn't stop play-acting to lighten the mood.

Baker Acting the patient, the crisis team arranged an emergency psychiatric evaluation to keep him safe.

When the stray dog barked, the opossum began acting possum to avoid attracting attention.

Although he's openly gay, his straight-acting demeanor often leads people to assume he's heterosexual.

The teenager is acting out because he feels ignored at home.

The kids were acting the maggot at the back of the classroom until the teacher told them to behave.

At the medieval fair, she was acting the jennet, imitating the low, ambling gait and dignified carriage of the small Spanish horse.

The self-acting valve closed when the pressure dropped, preventing a dangerous leak.

Clinicians preferred the faster-acting medication because it relieved symptoms sooner.

The fast-acting pain reliever reduced my headache within minutes.