Exploring the Meaning of Koinoo in Greek

κοινόω names the act of profaning—treating someone or something as defiled—in disputes about what truly makes a person unclean, in a vision about what God has cleansed, in a temple accusation, and in a ritual context that contrasts defilement with cleansing.

Occurrences

“That which enters into the mouth doesn’t defile the man; but that which proceeds out of the mouth, this defiles the man.” (Matthew 15:11)

Here κοινόω frames “defilement” as something that happens to “the man,” and the saying draws a sharp line between what comes from outside (food entering the mouth) and what comes from within (speech that “proceeds out of the mouth”). The verb assigns the decisive moral weight to the latter: what issues outward from the person is pictured as what profanes.

“But the things which proceed out of the mouth come out of the heart, and they defile the man.” (Matthew 15:18)

This explanation tightens the focus by tracing the source of what profanes: “the heart.” κοινόω is therefore tied to an interior origin that expresses itself in outward speech. The verb marks the person as the object affected—profanation is not merely a label on an action but a condition imposed upon “the man.”

“These are the things which defile the man; but to eat with unwashed hands doesn’t defile the man.” (Matthew 15:20)

κοινόω is used twice to compare two kinds of behavior. The repetition underscores a contrast between what is counted as truly profaning (“These are the things…”) and what is denied that status (eating “with unwashed hands”). The point is not that “unwashed hands” are desirable, but that this action is explicitly denied the power to profane the person.

“There is nothing from outside of the man, that going into him can defile him; but the things which proceed out of the man are those that defile the man.” (Mark 7:15)

In Mark, the same contrast is stated in a more absolute form: “nothing from outside… can defile him.” κοινόω functions as the verdict on what counts as profaning, and the sentence structure places all profaning power on what “proceed[s] out of the man.” The verb thus belongs to an argument about direction and source: outside-in is denied, inside-out is affirmed.

“He said to them, “Are you also without understanding? Don’t you perceive that whatever goes into the man from outside can’t defile him,” (Mark 7:18)

Here κοινόω appears in a question that presses for “understanding” and “perce[ption].” The verb is attached to a claim of inability—what enters from outside “can’t” profane. The rhetorical force is instructional: the audience is being corrected about what kinds of contact or intake should be feared as defiling.

“He said, “That which proceeds out of the man, that defiles the man.” (Mark 7:20)

This terse sentence uses κοινόω as a direct identification: the profaning agent is “that which proceeds out of the man.” With no added qualifiers, the verb carries the whole weight of the judgment. The briefness makes the claim sound like a settled principle: profanation is linked to what emerges from within the person.

“All these evil things come from within, and defile the man.” (Mark 7:23)

κοινόω concludes a summary about “evil things.” The phrase “come from within” parallels the earlier “proceeds out of the man,” and the verb seals the consequence: these inner-sourced realities “defile the man.” κοινόω therefore functions as the outcome of interior evil, portraying profanation as the condition produced by what is generated within.

“A voice came to him again the second time, “What God has cleansed, you must not call unclean.”” (Acts 10:15)

In Acts, κοινόω is voiced as a prohibition: once God has cleansed, it must not be treated as unclean. The verb shifts from diagnosing what profanes a person to forbidding a human act of declaring or treating something as profaned. In this scene, the decisive action belongs to God (“has cleansed”), and κοινόω names the opposite human response that is disallowed.

“But a voice answered me the second time out of heaven, ‘What God has cleansed, don’t you call unclean.’” (Acts 11:9)

This repetition anchors the point as a message “out of heaven.” κοινόω again appears as an imperative prohibition—do not “call” what God has cleansed “unclean.” The verb thereby carries an authoritative boundary: human assessment and treatment are to align with God’s cleansing action rather than reimpose profanation.

crying out, “Men of Israel, help! This is the man who teaches all men everywhere against the people, and the law, and this place. Moreover, he also brought Greeks into the temple, and has defiled this holy place!” (Acts 21:28)

Here κοινόω is deployed as a charge concerning sacred space: “has defiled this holy place.” The verb portrays profanation as an affront against what is “holy,” and the accusation places the alleged act within the temple. In the shouted appeal for help, κοινόω carries the weight of offense and alarm: it asserts that holiness has been violated.

“For if the blood of goats and bulls, and the ashes of a heifer sprinkling those who have been defiled, sanctify to the cleanness of the flesh,” (Hebrews 9:13)

In Hebrews, κοινόω describes a state—people “who have been defiled”—in a sentence about ritual materials and their effect. The verb sets up the need for a remedy: sprinkling “sanctif[ies] to the cleanness of the flesh.” κοινόω thus stands on the “before” side of a cleansing process, presenting defilement as something that can be addressed by sanctifying action aimed at bodily cleanness.

Sense and Usage

Across these passages, κοινόω consistently names profanation as an effect on an object—most often “the man,” once a “holy place,” and in Acts a category of things that people might “call unclean.” In the Gospel sayings, the verb is tightly linked to source: what comes from outside is denied the power to profane, while what comes from within (heart, inner evil, what proceeds outward) is affirmed as the true defiling agent. κοινόω therefore functions not as a vague religious label but as a decisive verdict in an argument about where impurity truly originates.

In Acts 10–11 the verb stands in the realm of classification and treatment: the issue is whether something that God has cleansed may still be regarded as unclean. κοινόω here is not describing a natural consequence (as in “evil things… defile the man”) but a human act of designating or treating something as profaned, an act explicitly forbidden in light of divine cleansing. In Acts 21:28 the verb moves into the public sphere of accusation, where profanation is a serious charge precisely because it targets “this holy place.” Hebrews 9:13, finally, places κοινόω within a cleansing-and-sanctifying contrast, where being defiled is the condition that makes talk of “cleanness of the flesh” meaningful.

Imagery

κοινόω carries vivid relational imagery: something crosses a boundary it should not cross and, by doing so, renders a person or place profaned. In the Gospel disputes, the boundary is pictured at the mouth—what enters versus what proceeds out—yet the decisive line is traced back to “the heart” and to what is “within.” In Acts, the boundary is drawn by God’s cleansing on the one hand and human speech (“call unclean”) on the other. In the temple accusation, the boundary is the holiness of a place that is said to have been violated. Hebrews sets the image of defilement against ritual sprinkling that results in “cleanness of the flesh,” portraying profanation as a condition that calls forth cleansing action.

Sources: Lexical data from Strong’s Exhaustive Concordance and the Translators Brief Lexicon of Extended Strongs for Greek (STEPBible, CC BY). Occurrence data from the Translators Amalgamated Greek New Testament (STEPBible, CC BY). Scripture quotations from the World English Bible (public domain).