rub up against
1． rub against sth．in passing擦上；相磨擦
Look at the spot on your skirt！You must have rubbed up against wet paint somewhere看看你裙子上的脏斑！你一定是在什么地方碰上没干的油漆了。
2．meet or come into contact with by accident 偶然相遇
You occasionally rub up against most interesting people in unlikely Places．有时在意想不到的地方会遇上很有趣的人。