Also found in: Dictionary.
insist on (something)
1. To need to do a particular thing, in spite of others' annoyance or discouragement. My little boy insists on taking his favorite toy truck with him every where he goes. Why do you insist on wearing shorts in the middle of winter? You look like a nut!
2. To require or dictate that something happen. I insist on you following my rules while you're living in my house.
insist (up)on something
to demand something. (Upon is formal and less commonly used than on.) I want you here now! We all insist upon it! I insist on it too.
1. To demand something firmly and persistently: I insist on peace and quiet when I'm trying to work!
2. To continue with some behavior or course of action in spite of the disapproval of others: He insists on tapping his fingers on the desk, even though I've told him to stop.