L

[let on]  {v.},  {informal}

1. To tell or admit what you know. — Usually used in the negative.

Frank lost a quarter but he didn't let on to his mother.

2. To try to make people believe; pretend.

[let one have it]  {v. phr.}

1a.  {slang}

To hit hard.

He drew back his fist and let the man have it.

Give him a kick in the pants; let him have it!

Syn.: [GIVE IT TO].

1b.  {slang}

To use a weapon on; to shoot or knife.

* /The guard pulled  […]

[let one in on]  {v. phr.}

To reveal a secret to; permit someone to share in.

[let one's hair down] or [let down one's hair]  {v. phr.},  {informal}

Act freely and naturally; be informal; relax.

Kings and queens can seldom let their hair down.

After the dance, the college girls let their hair down and compared dates.

 […]

[let one's left hand know what one's right hand is doing]  {v. phr.}

1. To make a show of your kindness or help to others. — Used in the negative.

* /The Bible tells us not to let the left hand know what the right hand is doing when we give to the  […]

[let oneself go]

See: [LET GO] (6).

[let out]  {v.}

1a. To allow to go out or escape.

The guard let the prisoners out of jail to work in the garden.

Mother won't let us out when it rains.

Compare: [LET LOOSE].

1b.  {informal}

To make (a sound) come out of the mouth; utter.

*  […]

[let pass]  {v. phr.}

To disregard; overlook.

[let ride]  {v. phr.},  {informal}

To allow to go on without change; accept (a situation or action) for the present.

The committee could not decide what to do about Bob's idea, so they let the matter ride for a month or so.

* /The class was rather  […]

[let sleeping dogs lie]

Do not make (someone) angry and cause trouble or danger; do not make trouble if you do not have to. — A proverb.