сотрудник

Whenever I find this word I have a doubt. In my dictionary says that it means "worker", "employee", but because of my Spanish language I think always of "co-operator", a concept beloved by the manager but that includes a different shade, a kind of will that isn't in "worker", "employee". Really a сотрудник isn't a "cooperator" but just a "worker", "employee" ? Thank you.

Cотрудник is just a co-worker, nothing else.

Yes, сотрудник is either a worker, or an employee, or also a cooperator. The last one is the closest one by structure. It's like "со-труд-ник" - "тот, кто трудится вместе)", as well as the "co-operat-or" :) But it's used for all 3 of them depending on the exact context.

Maybe like:
co-worker = коллега
worker = рабочий
employee = наёмный рабочий
cooperator = сотрудник

At least this sounds clumsy to me: "Рабочие нашего офиса всегда ответят на Ваши вопросы". Сотрудники would fit better. So it doesn't imply that сотрудник is being co-working with someone. It's just an office-worker, employee. But it's not a worker, who works with his hands. :)

Thank you. I see that here the "co" is somewhat lax.