What is a Ratcatcher slang for in Romeo and Juliet?

One who catches rats; particularly one who does so professionally. (Britain) An insult, not widely used nowadays but made popular by William Shakespeare in Romeo and Juliet.

What does the insult Ratcatcher mean?

One who catches rats

Ratcatcher definition
(UK) Insult, not widely used nowadays but made popular by Shakespeare in Romeo and Juliet. noun. 3. 4. One who catches rats; particularly one who does so professionally.