1. a pyromaniac, some who sets fire to random people, animals, or objects as a form of gratification

2. any arsonist
(from a type of insect that has nothing to do with fire despite it's name)

Firebug is NOT an animal and has NOTHING to do with a firefly or any animal a firebug is slang for an arsonist or a serial arsonist.

A girl who is so obsessed with meeting and dating firemen that she will start fires and put herself in danger to be rescued by them.

A sex worker utilizing a certain dating app for marketing purposes.

A screenshot of a web page with edited HTML. Stems from the Firefox add-on Firebug, but can be done on some other browsers as well.