Exploring the Meaning of Katphtheiro in Greek

καταφθείρω means “to deprave.” It appears once in the New Testament, in Paul’s description of opponents of the truth in 2 Timothy 3:8.

Root and Related Words

καταφθείρω is formed with the preposition kata (κατά), “according to” (Strong’s G2596), joined to phtheiro (φθείρω), “to destroy” (Strong’s G5351). In combination, the prefixed form presents depraving as an action that works downward into a person’s inner life, not merely touching the surface but pressing through what is “according to” or throughout a thing.

Occurrences

“Even as Jannes and Jambres opposed Moses, so these also oppose the truth, men corrupted in mind, who concerning the faith are rejected.” (2 Timothy 3:8)

In this verse the word sits inside a compact chain of descriptions, each phrase sharpening the portrait of a certain kind of opponent. The comparison (“Even as Jannes and Jambres opposed Moses…”) frames the situation as active resistance rather than passive misunderstanding: “so these also oppose the truth.” Within that setting, καταφθείρω supplies the moral and intellectual condition that fits such opposition—these are “men corrupted in mind.” The depraving is presented as affecting the mind, the place from which opposition to the truth proceeds and by which a person evaluates what is true.

The immediate context in the sentence makes the depraving more than a private flaw. It stands between two public outcomes: first, they “oppose the truth,” and then, “concerning the faith are rejected.” The corruption of mind provides a stated basis for the rejection: their stance toward “the faith” is judged in light of an inner condition described as corruption. Paul’s wording does not isolate a single bad act; it depicts a state of depravity that characterizes the people themselves (“men corrupted in mind”). The phrase functions adjectivally, defining what sort of men they are, and thus why their opposition has the weight and danger that the comparison implies.

Sense and Usage

The definition “to deprave” comes into focus here as an inward ruining of the person’s mental and moral capacity as it relates to truth. In 2 Timothy 3:8, depravity is not framed as ignorance needing information, but as corruption lodged within the mind. Because the verse links this mental corruption with active opposition—“these also oppose the truth”—the depraving has an outward-facing effect: it produces resistance rather than receptivity. The word thus serves to describe a distortion at the level where truth is recognized, weighed, and either embraced or resisted.

Paul further ties this depravity to an evaluative outcome: “concerning the faith are rejected.” Within the single sentence, the mind corrupted by depravity leads to a stance toward truth that brings rejection in matters of faith. The depraving is therefore consequential. It is not presented as a neutral psychological condition, but as a corruption with spiritual and communal implications, because it bears directly on “the truth” and on “the faith.” The verse’s structure places depravity as a central explanatory term: opposition to truth is the behavior; corruption in mind is the condition; rejection concerning the faith is the resulting verdict.

The presence of the comparison to “Jannes and Jambres” intensifies the sense of depraving without adding extra details of the act itself. The reader is meant to hear “opposed Moses” and immediately grasp that these present opponents belong to the same moral category: they are not merely debating; they are resisting what they should not resist. In that rhetorical frame, καταφθείρω marks the opposition as rooted in a mind made corrupt—depraved in a way that inclines it against the truth. The word’s force, in this usage, is diagnostic: it names the inner moral-spiritual disfigurement that stands behind the outward opposition.

Imagery

Although the verse does not use a visual metaphor, “corrupted in mind” carries a strong implied picture of something inward that has spoiled. The mind is depicted as a place that can be damaged by depraving, such that what should be aligned with “the truth” becomes disordered and unfit, leading to rejection “concerning the faith.”

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).