Democrats will need to do some teaching about impeachment:

32% correctly identified impeachment as an indictment by the House, causing a trial in the Senate.
5% said it means the House censures an official
13% said the official is censured and removed from office
7% said criminal proceedings against a person start once they are impeached
28% didn’t know
6% said none of them apply.

54% of people said they either generally knew or thoroughly understood the concept.

businessinsider.com