Definitions

1. noun

A person who imitates or pretends to be brave or manly, often in a way that is considered to be insincere or childish.

“He was called a sissier for running away from the fight.”

2. verb

To act or behave in a way that is considered to be weak or cowardly.

“After being teased, he began to sissier in front of his classmates.”