To add or increase (something, such as criticism) abundantly or excessively. 1. To accumulate: Work is piling up.

Is pile up an idiom?

1. To accumulate, gather, or increase over time. With Deborah out sick all week, jobs have begun to pile up in our department. ...

What is meant by piling on?

1 : to put a large amount of (something) on something or someone He piled on the gravy. The teacher punished the class by piling on more homework. Her parents piled on the pressure to do well in school. 2 : to gained a lot of something He piled on the pounds after he got married.