1. To clog or obstruct something. Ugh, who jammed up the printer this time?
2. To quickly move or push something upwards. In this usage, a noun or pronoun can be used between "jam" and "up." Hey, be careful! If you jam those boxes up, you'll break something. I jammed the stick up a few times but couldn't get the ball out of the tree.
3. To cause something to clog or obstruct something else. In this usage, a noun or pronoun can be used between "jam" and "up." Ugh, what jammed the printer up this time? Oh, some crumpled pieces of paper.
1. and jammed mod. in trouble. (From in a jam.) He got himself jammed up with the law.
2. mod. glutted; full of food or drink. I’m jammed up. I can’t eat another bite.