四字熟語 - Yojijukugo are four-character compound word that then form an idiomatic phrase, a phrase that often means a lot more than the four characters that composes it.

Quite often it often derives from the Japanese or Chinese culture that spawned the word, much like English idioms. For example, if I say "That came from out of left field" you would know that whatever the phrase was referring to was crazy or unexpected. What you may not know is that the phrase owes it's existence to the Chicago Cubs. You see, the Cubs, before they played at Wrigley Field, used to play across from an insane asylum. Where was the asylum? You guessed it, just beyond the left field limits.

The characters are typically paired up forming subphrases that combine to make the whole phrase.

Even 四字熟語 is a yojijukugo

四 - よ, yo, four
字 - じ, ji, letter - self evident - four letter

熟 - じゅく, juku, mature
語 - ご, go, word - actually means idiom
So all together a four kanji idiomatic phrase.

I heard Taigu use this phrase in english in the Rakusu videos

一石二鳥, いっせきにちょう ,Isseki nichō
一 - one
石 - stone
二 - two
鳥 - bird
Killing two birds with one stone.

But since we're Buddhists, perhaps we should say
一挙両得, いっきょりょうとく, Ikkyo ryōtoku
One + Behavior + Both + Gain
Doing one action to gain two things
It's an expression that comes from a history book about Jin Chinese dynasty.

And now one from Buddhist culture
会者定離 ,えしゃじょうり, eshajōri
meeting + person + always + be separated
Every meeting must involve a parting; Those who meet must part.

And on that note I will take my leave.

Gassho
Sat
Inconsistent student of Japanese for 7 years, no JLPT taken.