What is a fronter? I am trying to apply for a job at a call center and found many entries with the?

It's a nice way of saying "liar". You'll be expected to pretend you believe (or are) a certain thing in order to conceal your real intention. As an example, you may have to pretend you are a sportsperson or former sportsperson in order to persuade other sportspeople into buying services. That's just an example and its liable to be nothing to do with sports.