It comes down to the root word "rob", meaning slave [1]. There is probably an o->a shift going from west to east slavic. From "rob" you get "robota", or work, a

It comes down to the root word "rob", meaning slave [1]. There is probably an o->a shift going from west to east slavic. From "rob" you get "robota", or work, and "robotnik" is "robota" + "-nik", meaning a person who performs robota. The other word you can see used is служба, or servitude, which comes with less slavery connotations. You would never call a slave "слуга", servants are paid, not owned. [1] https://en.wiktionary.org/wiki/rob#Czech https://en.wiktionary.org/wiki/rob#Czech - The page also lists several other slavic languages where it has the same meaning and has links to the proto-slavonic term