play possum

verb3

1. •
   To feign death; to remain quiet and still to escape attention or remain undetected; to lie low.

   • Thinking fast, we played possum, hoping the bear wouldn't bother us.
   • The soldier played possum, fooling the sniper.
2. •
   To feign sleep, illness, etc.

   • When we used to get home late at night, I would play possum so my daddy would carry me inside and put me in bed.
3. •
   (old-fashioned) To dissemble or to feign ignorance; to disguise or conceal something in order to deceive.

   • Though, as it afterwards turned out, the Yankee had money enough about him, and was merely playing the ’possum all the while. — 1833