Mama bear phrase
A strong mother, who behaves threateningly and angrily towards whoever touches, harms, or intends to harm her kid(s).
When a stranger gave me candy, my mom turned into a mama bear and told him to go away.
Mary acted like a mama bear when an unknown man patted her daughter on the shoulder.
A female member of the police.
A mama bear signaled us to stop, then we were made to dismount and show our documents.
The drunken man attacked the mama bear, but she managed to bring him down.
The first meaning originated from the fact that mother bears act in a notoriously violent and aggressive way when confronting a danger to their offspring.
Used to advise that someone should wear warm or dry clothes, otherwise he or she will catch a very bad cold
"It's snowing outside, you'll catch your death of cold if you don't wear properly."