Which of the following is NOT typically considered an occupation?

The term "occupation" generally refers to a person's job or profession—activities that involve work or labor performed for financial gain. In this context, teacher, doctor, and engineer all represent occupations in that they require specific training and skills, and individuals in these roles are actively engaged in work that provides services or products in exchange for compensation.

On the other hand, a retiree is someone who has ceased working in their career and is no longer engaged in an occupation. Retirees may draw a pension or social security but do not participate in a formal job or profession. Thus, "retiree" stands out as it does not fit into the category of active occupations where individuals are working and contributing to the economy.