Don't use un, una when giving people's professions (zero article)

We don't use the indefinite article un, una when talking about professions.

Read and listen to these examples:

Notice that we literally say:

Also note that most of the time the job titles are different for men and women. Here is a list of ordinary professions.

However, if you are giving extra information adding a quality adjective, you always need article "un/una" in front:

See also Artículo cero o ausencia de artículo and Artículo