let in
phr. v.. B1 Intermediate Oxford
phr. v.. to allow someone or something to enter a place or situation.
phr. v.. to permit the entry of a person or object into a space; transitive phrasal verb with the particle 'in' indicating direction or access.
Can you let me in?
The security guard let the visitor in after checking their ID.
The old man, despite his age, let the stray cat in during the storm.
Usage
takes a direct object — the person or thing being allowed entry.
Teaching tip
contrast with 'let out' (to allow exit) and note that 'let in' is inseparable — the object must come before the particle.
Pitfall
Let in himLet him inthe object precedes the particle in separable phrasal verbs; 'let in' is inseparable.