This Greek word is found in 2 Thessalonians 2:6–7 in an eschatological context: Christians must not be concerned as if the Day of the Lord would happen tomorrow, since the man of lawlessness (Antichrist) must be revealed before it occurs.

St. Paul the Apostle then adds that the Antichrist's emergence is conditional upon the removal of "something/someone that restrains him" from becoming fully manifested. Verse 6 uses the neuter gender, τὸ κατέχον; and verse 7 the masculine, ὁ κατέχων.

Since Paul does not explicitly mention the katechon's identity, the passage's interpretation has been subject to extensive dialogue and debate amongst Christian academics.

The biblical term katechon is not widely known or discussed in the religious world. I would like to know your opinion on it and its possible synonymy with the modern term taboo.

From Wikipedia's article:

The katechon (from Greek: τὸ κατέχον, "that which withholds", or ὁ κατέχων, "the one who withholds"), also known as the restrainer, is a biblical term referring to something that must be removed before the arrival of the "man of sin." Mentioned in the New Testament, the katechon's uncertain identity has been debated amongst Christian scholars. Common interpretations for the identity include the government, the church, and the Holy Spirit.

https://en.wikipedia.org/wiki/Katechon