"Kolega" is a male who is your friend. "Koleżanka" is a female who is your friend. Both maybe a presons which you like and othen meet with them,or just someone you work with.

Kolega - male friend Koleżanka - female friend You can also say - znajomy (male), znajoma (female).

Colega*, Es tu compañero de trabajo, puede ser hombre o mujer

I think this word might be tricky. Kolega/koleżanka in Polish is actually any person you have met and have certain relationship with, as long as none of them is superior to the other (either position or age). This can possibly be a schoolmate, a mother of your child's friend, a random neighbour or so. When you mean a person you trust more than the others, the name for them is przyjaciel/przyjaciółka (best friend). Eg. when you're a school child, everybody in your class is your kolega but only a few of them are przyjaciel.