[troupo]

The word has other meanings, too ;) E.g. "professional conduct" isn't one that is paid for:

1a. of, relating to, or characteristic of a profession

1c.1. characterized by or conforming to the technical or ethical standards of a profession

3. following a line of conduct as though it were a profession

[projektfu]

Professionals can be unprofessional, and amateurs can show professionalism, but only one gets paid.