Temporarily assuming the duties of another
The art and occupation of an actor
A display of insincere behavior
She is acting responsibly in his behalf.
If he was angry, he certainly wasn't acting like he usually did.
You're acting like a kid.
Hardly. She's not capable of acting anyone's interest but her own. And, if I don't try to get you out of here, she'll still take you and your baby's souls.