ἀκάθαρτος

unclean, impure

Definition

The adjective ἀκάθαρτος (akathartos) fundamentally means 'unclean' or 'impure,' describing that which is ritually, morally, or spiritually defiled and thus unfit for God's holy presence. In the Gospels, it most frequently describes 'unclean spirits' or demons (e.g., Mark 1:23, 5:2), spiritual beings opposed to God's kingdom. It also denotes ritual impurity under the Mosaic Law, as in the case of leprosy or certain foods (implied in passages like Acts 10:14). The term carries a strong connotation of separation from what is holy and acceptable to God.

Biblical Usage

ἀκάθαρτος is used 29 times in the New Testament, predominantly in the Synoptic Gospels (Matthew, Mark, Luke) and Acts. Its primary usage is in the phrase 'unclean spirit' (πνεῦμα ἀκάθαρτον) to identify demonic forces (e.g., Matthew 10:1, Mark 3:11). In Acts and the Pauline epistles, it expands to include the concept of moral and ritual impurity, such as unclean foods (Acts 10:14) and the defilement of idols (2 Corinthians 6:17).

Etymology

Derived from the alpha-privative ἀ- (a-), meaning 'not' or 'without,' combined with the adjective καθαρός (katharos, G2513), meaning 'clean, pure.' Thus, it literally means 'not clean' or 'unpurified.' This construction highlights a state of deficiency or corruption from a presumed standard of purity.

Semantic Range

This word is central to understanding the biblical concepts of holiness, sin, and redemption. It delineates the barrier between a holy God and a defiled humanity and creation. Jesus's authority over 'unclean spirits' demonstrates his power to cleanse and restore what is defiled, a key theme of his ministry. Understanding this term enriches reading by clarifying the comprehensive nature of Christ's work to purify people from all forms of spiritual and moral defilement (see Ephesians 5:5).

In a Jewish context, 'unclean' (akin to the Hebrew טָמֵא, tame) was a powerful cultic and social category from the Old Testament Law (Leviticus). It referred to physical conditions, foods, or objects that rendered a person ritually unable to approach God's sanctuary. The New Testament, especially in Jesus's teachings and Peter's vision in Acts 10, redefines and internalizes this concept, shifting focus from external ritual to the moral and spiritual condition of the heart.

κοινός (koinos, G2839) — common, profane; often used for ceremonially unclean things. μολυσμός (molusmos, G3436) — defilement, corruption; emphasizes moral stain or pollution. πονηρός (ponēros, G4190) — evil, wicked; broader term for moral evil, sometimes used of evil spirits.

Word Details

Scripture References