Greek word · G801

ἀσύνετος

asynetos

senseless

Without understanding, lacking insight, unable to put things together (from a-, 'not', plus synesis, 'understanding', literally 'bringing together').

Appears 5 times in 5 verses of the Greek New Testament. · Updated October 31, 2026

What it means

ἀ-σύνετος, -ον

without understanding or discernment: Matthew 15:16, Mark 7:18 (Swete, in l), Romans 1:21, 31 10:19 (for an ex. of its use in the moral sense, see MM, see word).†

(AS)

From G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922), via STEPBible.org (CC BY 4.0).

Range of meaning: Without understanding, lacking insight, unable to put things together (from a-, 'not', plus synesis, 'understanding', literally 'bringing together').
Against the English: 'Foolish' (BSB, KJV, ESV, NIV) can sound like 'silly'. The Greek means lacking discernment, unable to connect evidence to its meaning. WEB 'senseless' and YLT 'unintelligent' are closer.
Used elsewhere in the period: LXX Ps 91:7 (Eng. 92:6), 'the senseless man does not know'; Sir 15:7; Wis 11:15 links 'senseless reasonings' with idol worship. Rom 1:31 uses the same word in the vice list; Matt 15:16.

Range of meaning: "Without understanding, senseless, foolish" (BDAG). It is the negative of συνετός, "intelligent, discerning." It means a failure to grasp or put things together, often with moral and religious overtones.
Against the English: "Without understanding" (BSB, NASB), "void of understanding" (WEB), "unintelligent" (YLT), "foolish" (KJV, ESV), "that has no understanding" (NIV). "Foolish" matches the Hebrew naval, which means godless, morally obtuse folly (compare Nabal in 1 Sam 25), more than low intelligence.
Used elsewhere in the period: It renders Hebrew naval in Deut 32:21 LXX. Elsewhere in the LXX: Ps 92(91):6; Sir 15:7; Wis 1:5; 11:15. In Paul: Rom 1:21 ("their senseless heart was darkened", of idolaters), Rom 1:31 (in the vice list), and here. Jesus uses it of the disciples in Matt 15:16 and Mark 7:18.

Range of meaning: Literally "without σύνεσις". Σύνεσις is the faculty of "bringing together": connecting things, seeing what they mean, discerning. Ἀσύνετος therefore covers dull, senseless, undiscerning, foolish. In Jewish wisdom writing this is never purely intellectual. The person without understanding fails to see how God's order works and acts accordingly, so the word carries a moral edge.
Against the English: Brenton and the KJV say "the indiscreet". In 1611 that meant "lacking discernment", but today it suggests tactlessness or leaking secrets. The WEB's "people void of understanding" is closer. The NRSV's "stupid people" is blunt and may sound like low IQ, which is narrower than the Greek.
How it drifted: English "discreet" comes from Latin discernere, "to separate, distinguish". It originally meant "discerning, judicious". Since then it has narrowed to "careful not to embarrass or reveal", so "indiscreet" now hears as a social or secret-keeping failure rather than a lack of judgement.
Used elsewhere in the period: In the Greek Old Testament it often translates Hebrew words for the fool or the one without understanding (e.g. Ps 92:6 [LXX 91:7]). It is common in Sirach, where the asynetos is set against the synetos (the one with understanding; e.g. Sir 3:29, 9:14–15, 22:13–15). The New Testament uses it the same way: "Are you also still without understanding?" (Matt 15:16), and "their senseless heart" (Rom 1:21).

Matthew · 1

Matthew 15:16 ἀσύνετοί without understanding

“Do you still not understand?” Jesus asked.

Here: Literally “un-put-together.” Someone who cannot connect what they hear into real insight. A sharp word in Jewish Scripture, used of a people who fail to perceive God’s ways (Deut 32:21 LXX). It does not mean low intelligence.

Mark · 1

Mark 7:18 ἀσύνετοί without understanding

“Are you still so dull?” He asked. “Do you not understand? Nothing that enters a man from the outside can defile him,

Here: Lacking the ability to put things together and grasp their meaning. It echoes Jesus' command to the crowd in v14, 'hear me, all of you, and understand (synete)', so the disciples are failing exactly what he had just asked for.

Romans · 3

Romans 1:21 ἀσύνετος foolish

For although they knew God, they neither glorified Him as God nor gave thanks to Him, but they became futile in their thinking and darkened in their foolish hearts.

Here: Literally 'not putting things together'. A heart that cannot connect what it sees to what it means. It can be read as 'so that it became senseless'.
Romans 1:31 ἀσυνέτους, foolish,

They are senseless, faithless, heartless, merciless.
Romans 10:19 ἀσυνέτῳ without understanding

I ask instead, did Israel not understand? First, Moses says: “I will make you jealous by those who are not a nation; I will make you angry by a nation without understanding.”

Here: "Without insight." Paul used this word for idolatrous Gentiles in 1:21 and 1:31. The irony is sharp: the people with no understanding come to know God, while Israel, which had the oracles, stumbles.

Word data: STEPBible.org (CC BY 4.0), main text only.