A university student who is enrolled in school full time and not seeking employment is considered:

Such a student is considered to be out of the labor force.

The term 'not in labor force' refers to people who are either not working or not actively looking for a job either - so, students, retired persons, and people who are taking care of other family members. On the other hand, people who are working (at least part-time jobs) are considered in the labor force, its participants.