When reading the Hebrew Bible in a modern translation, the narratives often appear remarkably polite and sanitized when dealing with human reproduction and sexuality. However, this is largely an illusion created by translation. Biblical Hebrew is an intensely physical, earthy language, but it operates within a strict ancient Near Eastern code of modesty and honor.
Rather than using clinical or explicit anatomical terms, the ancient scribes employed a rich, highly specific system of euphemisms to discuss sexual relations and human genitalia. For historical-critical scholars, decoding these ancient idioms is crucial, because a literal, word-for-word reading often obscures the profound theological, legal, and sometimes scandalous realities of the original text.
Here is a breakdown of the most prominent sexual euphemisms in the biblical corpus and what they reveal about the ancient Israelite worldview.

The Epistemology of Intimacy: “To Know”

The most famous and widely recognized biblical euphemism for sexual intercourse is the Hebrew verb yada, which translates literally as “to know.” This usage appears at the very beginning of the biblical narrative in Genesis 4:1: “And Adam knew Eve his wife; and she conceived.”
In the modern, Western world, knowledge is primarily an intellectual exercise—the accumulation of facts in the brain. But in the ancient Near East, knowledge was deeply experiential and relational. By using yada to describe sexual intercourse, the biblical authors were making a profound theological statement. Sex was not viewed merely as a biological function or a casual physical act; it was the ultimate act of vulnerability, discovery, and mutual recognition. To “know” someone sexually was to enter into the deepest possible covenantal intimacy with them, intertwining two lives on a fundamental level.

The Mystery of the “Feet”

When it comes to human anatomy, the biblical writers were exceptionally careful. Rather than naming the male or female genitalia directly, they frequently utilized a polite anatomical stand-in: the feet (raglayim).
This euphemism explains several strange passages that baffle modern readers. For instance, in Isaiah 7:20, the prophet warns that the invading Assyrian army will act as a razor that shaves “the hair of the head and the hair of the feet”—a humiliating threat of forced, total exposure and genital shaving. Similarly, in the throne room vision of Isaiah 6, the seraphim use their wings to cover their faces and their “feet,” an act of supreme modesty in the presence of the divine.
The most famous narrative use of this euphemism occurs in the Book of Ruth. In chapter 3, Naomi instructs Ruth to go to the threshing floor at night, uncover the sleeping Boaz’s “feet,” and lie down. While traditional interpretations often sanitize this scene as a purely innocent gesture of subservience at the bottom of his bed, historical-critical scholars recognize the heavy, provocative ambiguity of the text. Ruth is engaging in a highly daring, culturally loaded act of propositioning Boaz for marriage, utilizing language that intentionally skirts the edge of sexual scandal.

Swearing by the “Thigh”

In the patriarchal narratives of Genesis, readers encounter a bizarre oath-swearing ritual. When the elderly Abraham makes his servant swear to find a suitable wife for Isaac, he commands the servant: “Put your hand under my thigh, and I will make you swear by the Lord” (Genesis 24:2). Jacob makes his son Joseph perform the exact same ritual in Genesis 47:29.
In Biblical Hebrew, the “thigh” or “loins” (yarek) is a standard euphemism for the reproductive organs and the seat of procreative power (hence the later idiom of children “coming from the loins” of their ancestors). Placing a hand under the patriarch’s thigh was not a random physical gesture; it was a deeply solemn oath sworn on the patriarch’s genitalia.
This had a dual significance. First, because the oath usually pertained to the continuation of the family line, the servant was swearing upon the very source of that lineage. Second, for the ancient Israelites, this specific anatomical region bore the physical mark of the covenant with God: circumcision. The servant was effectively swearing on the sacred covenant itself, acknowledging that a failure to keep the promise would result in divine cursing upon his own life.

The Legal Code: “Uncovering Nakedness”

While narrative texts use poetic idioms like “knowing” or “feet,” the legal texts of the Torah require absolute precision to dictate law. In the Book of Leviticus, particularly in the strict sexual codes of chapter 18, the authors use the specific phrase “to uncover the nakedness of” (galah ervah).
Unlike yada, which is used for sanctioned, marital intimacy, “uncovering nakedness” is an explicitly negative legal term. It is used exclusively to describe illicit, forbidden, or incestuous sexual relations.
In the honor-shame culture of the ancient Mediterranean, a person’s honor was deeply tied to the modesty and sexual fidelity of their family members. To “uncover the nakedness” of a relative was not just a violation of a purity law; it was an act of profound social violence that stripped the family of its honor. The euphemism highlights the shame and exposure inherent in the crime, legally defining sexual sin as an act of humiliating theft against the patriarchal household.
Ultimately, the biblical text is far from prudish. The scribes were writing about the messy, complex realities of human biology and desire. By utilizing this system of euphemisms, they managed to record legal boundaries, scandalous propositions, and profound marital intimacy without ever violating the ancient cultural boundaries of modesty.