let up on

let up on somebody

to make less of an effort to get someone to do something Teachers let up on us when we were seniors, probably figuring they'd taught us as much as we'd ever learn.

Usage notes: often used in the form not let up on someone: The police said they would not let up on drug dealers.

See also: let, up

let up on something

to make less of an effort to do something NASA eventually let up on trying to convince the public that every astronaut was happily married.

See also: let, up