let

1 let /ˈlɛt/ verb
lets; let; letting
1 let
/ˈlɛt/
verb
lets; let; letting
Britannica Dictionary definition of LET
1 
[+ object] : to allow or permit (someone or something) to do something
Usage Let is followed by a verb that has the form of the infinitive without to.
Let is never used as be let; use be allowed or be permitted instead.
2 
[+ object]
a  — used in speech when you are making a polite offer to help someone
b  — used to introduce a polite statement or request
c  formal — used to introduce a command
— sometimes used figuratively in a way that is not formal
d  — used to express a warning
3 
a 
◊ Let's and (more formally) let us are used to introduce statements that express a wish, request, suggestion, or command.
b 
◊ The phrase let's go is used in speech to tell someone to go or work faster.
c 
◊ The phrase let us pray is used to introduce a prayer.
d 
◊ The phrases let's face it and let's be honest are used to say that something is true and cannot be denied.
4 
a  [+ object] : to allow someone to use (something) in return for payment : rent
b  [no object] chiefly British : to be rented or leased for a specified amount of money
5 
always followed by an adverb or preposition, [+ object] : to allow (someone or something) to go, pass by, etc.

let alone

1 
— used to refer to something that is even less likely or possible than the thing previously mentioned
2 
let (someone or something) alone : to not bother or touch (someone or something)

let bygones be bygones

— see bygones

let down

[phrasal verb]
1 
let (someone) down
a  : to fail to give help or support to (someone who needs or expects it) : disappoint
— sometimes used figuratively
b  : to make (someone) unhappy or displeased by not being as good as expected
— see also letdown
2 
◊ To let someone down easy/gently is to give someone unpleasant news in a gentle or kind way.
3 
let (something) down or let down (something)
a  : to cause or allow (something) to move down gradually
b  : to make (a skirt, a pair of pants, etc.) longer
— see also let your hair down at hair

let fly

or let fly with
— see 1fly

let go

1 
or let (something or someone) go or let go of (something or someone) or let go (something or someone) : to stop holding or gripping something or someone
— often used figuratively
2 
or let (yourself) go : to behave in a very free and open way
3 
let (someone) go
a  : to allow (someone who is being held as a slave, prisoner, etc.) to be free
b  : to officially make (someone) leave a job
4 
let (yourself) go : to fail to take care of (yourself)

let it all hang out

informal
: to show your true feelings : to behave in a very free and open way

let loose

— see 1loose

let me see

or let's see or let me think
— used in speech by someone who is trying to remember something

let off

[phrasal verb]
1 
let (someone) off or let off (someone) : to allow (someone) to get off a bus, an airplane, etc.
2 
let (someone) off : to allow (someone who has been caught doing something wrong or illegal) to go without being punished
— often used in the phrase let (someone) off the hook
3 
let off (something) : to cause (something) to explode or to be released in a forceful way — see also let off (some) steam at 1steam

let on

[phrasal verb]
1 
let (someone) on or let on (someone) : to allow (someone) to get on a bus, an airplane, etc.
2 
let on or let on (something) informal : to tell, admit, or show that you know something
3 
US, informal : to pretend or seem

let out

[phrasal verb]
1 
let (something or someone) out or let out (something or someone) : to release (something or someone)
— see also letout
2 
let (something) out or let out (something) : to make (a skirt, a pair of pants, etc.) larger
— opposite take in at 1take
3 
US, of a school : to end a semester, year, or session

let rip

— see 1rip

let sleeping dogs lie

— see 1dog

let (someone) have it

informal
: to attack, punish, or criticize (someone) in a violent or angry way

let (someone) in on (something)

: to allow (someone) to know (a secret)

let (someone) know

— see 1know

let (someone or something) be

: to not bother or touch (someone or something)

let (something) be known

— see 1know

let (something) slip

or let slip (something)
— see 1slip

let the cat out of the bag

— see cat

let the grass grow under your feet

— see 1grass

let up

[phrasal verb]
1 
: to stop or become slower
— see also letup
2 
let up on (someone) : to treat (someone) in a less harsh or demanding way
3 
let up on (something) : to apply less pressure to (something)

let (yourself) in for

: to cause (yourself) to have or experience (something bad or unpleasant)
2 let /ˈlɛt/ noun
plural lets
2 let
/ˈlɛt/
noun
plural lets
Britannica Dictionary definition of LET
[count] tennis
: a serve that is not accepted or allowed officially and must be done again

without let or hindrance

chiefly British, law
: without being interfered with