let through

Related to let through: let up

let through

1. To allow someone or something to quickly pass by one. A noun or pronoun is used between "slip" and "through." Don't let anyone through. We don't want the scene of the crime to be contaminated before the detectives have a chance to look things over. Their goalkeeper is not in his usual form today—that's the fourth goal he's let through already!
2. To allow someone or something make their or its way through a crowd of other people or things. A noun or pronoun is used between "slip" and "through." Excuse me, please let me through, I need to get to the back of the auditorium. Make sure to always pull over to let emergency vehicles through when you're in traffic.
3. To fail to detect someone or something. A noun or pronoun is used between "slip" and "through." She has an eagle eye for mistakes—she hasn't let a single error through since she started proofreading for us. The inattentive security guard kept letting prisoners through into the storage room where contraband is stored.
See also: let, through
Farlex Dictionary of Idioms.

let someone or something through (something)

to permit someone or something to move through an opening or through a congested area. The usher wouldn't let me through the door. Please let the ambulance through the crowd.
See also: let, through
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • Don’t make a federal case out of it!
  • (someone's) secret is safe with (one)
  • don't count your chickens
  • don't bet on it
  • don't go there
  • don't get me wrong
  • don't beat a dead horse
  • all in (one's) head
  • discipline
  • discipline (one) for (something)