hamayvin yavin

"Hamayvin yavin" is a marvelous and recursively meaningless Hebrew idiom, literally "The one who understands will understand". It's often used to end an explanation while it is still cryptic, or at least before it becomes overbearing. It can also be used to exclude the clueless from a converstation or a lecture: I don't need to go on, I've been perfectly clear, and besides, hamayvin yavin.

The best use of this phrase ever is in the Biblical commentary of the 11th century Spanish Biblical exegite Rabbi Abraham Ibn Ezra. Ibn Ezra was foremeost a grammarian, and his readings of the Bible led him to conclude that its constant variations of language could be the result of multiple authorship. However, he didn't dare proclaim this openly, so within his commentary on the Bible, whenever he approached a controversial insight, he left his point unclear and simply concluded, hamayvin yavin.

Update: In response to TheLady, I know that the word hamayvin means "the understander" and not "the one who understands," but I think that the phrase is nonetheless recursive, or at least truistic, insofar as it consists of two words built on the same root. On a tenuously related note, the Hebrew word mayvin is the same as the Yiddish word maven, meaning an expert.

While the connotations and provenance above are perfectly correct, I should like to point out that the expression is by no means criptic or recursive - not for the Hebrew speaker, that is.

In Hebrew, the present singular conjugation in this particular form is often - in fact almost always - a noun as well as a verb. This allows for the creation of many common nouns from verbs: the Hebrew words for teacher (more), for example, also means teaches, and I suppose in common translation would be put in English as "he who teaches". There are other Hebrew idioms that make use of this structure, such as mevin davar - he who understands a thing, and yode'a inyan - he who knows a business, or his business; both describing a person of experience or education. (The ha at the beginning of hamevin is the Hebrew definite article, or "the")

So (ha)mevin in this context means rather "the understander" than simply "one who understands". It's a bit clumsy in English because it doesn't have nouns of this type (Gritchka kindly informs me that the technical term is active participle or noun of agent), and a concept like this would have to be expressed in several words: "a clever person", "a man of intelligence" or something to that effect.

Seen in this light, hamevin yavin is more of a banal truism than a recursive quip, although it is indeed often used to justify a criptic statement, or obfuscate instead of illuminate.