An adjunct professor performs a supplementary role in schools and colleges. They do not possess full-time responsibility, which means that they do not have the same benefits as full-time professors. Universities profit from hiring adjunct professors and these professors can work more flexible hours and require a lesser income bracket.
On the other hand, an associate professor is someone who fits in the tenured and tenure track roles in a teaching situation. They are often grouped as mid-level professors. Also, they are full-time members who can execute graduate or undergraduate roles as teachers. Associate professors are typically college professors.