English word origin

Etymology of slack

From Middle English slak, from Old English slæc (“slack”), from Proto-Germanic *slakaz. For sense of coal dust, compare slag.

5 source sectionsExtended source reportWiktionary original ↗

In this entry · 5 source sections

The source etymologies

Wiktionary via Kaikki / Wiktextract

The source reports below are imported and unreviewed by *SET-U. Separate numbered origins and differing source variants are preserved; agreement within this extraction is not independent corroboration.

Source etymology 1

Original entry ↗

adj

Lax; not tense; not firmly extended. · Weak; not holding fast. · Moderately warm. · Moderate in speed.

adv

Slackly.

noun

The part of anything that hangs loose, having no strain upon it. · A dip in a surface. · In particular, a shallow dell or hollow; a dip in the surface of terrain, such as between hills. · A low-lying marsh or a pool, especially a tidal or intermittent one which periodically fills and drains.

Selected source glosses provide context, not a complete modern definition inventory

From Middle English slak, from Old English slæc (“slack”), from Proto-Germanic *slakaz. For sense of coal dust, compare slag.

Relationships mentioned by the source

These are extracted mentions, not a timeline or a verified sequence of immediate parents.

Root classification mention*(s)leg-ine-pro
Inherited-form mentionslakenm
Inherited-form mentionslæcang · slack
Inherited-form mention*slakazgem-pro

This page abbreviates 8 auxiliary source items. The etymology narrative is not shortened. Omission counts are available in the audit fields below; consult the original for complete auxiliary material.

Inspect preserved source fields

Raw extraction fields are retained for auditing. Their order does not establish ancestry.

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Source etymology 2

Original entry ↗

verb

To slacken. · To mitigate; to reduce the strength of. · To lose cohesion or solidity by a chemical combination with water; to slake. · To refuse to work as hard as one is supposed to.

Selected source glosses provide context, not a complete modern definition inventory

From Middle English slakken, slaken, from Old English slacian, from Proto-Germanic *slakōną (“to slack, slacken”).

Relationships mentioned by the source

These are extracted mentions, not a timeline or a verified sequence of immediate parents.

Inherited-form mentionslakkenenm
Inherited-form mentionslacianang
Inherited-form mention*slakōnągem-pro · to slack, slacken

Inspect preserved source fields

Raw extraction fields are retained for auditing. Their order does not establish ancestry.

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Source etymology 3

Original entry ↗

noun

A temporary speed restriction where track maintenance or engineering work is being carried out at a particular place.

Selected source glosses provide context, not a complete modern definition inventory

Either from the adjective in Etymology 1 or the verb in Etymology 2.

Inspect preserved source fields

Raw extraction fields are retained for auditing. Their order does not establish ancestry.

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Source etymology 4

Original entry ↗

noun

A valley, or small, shallow dell; a sag or saddle in a ridge. · A flat-bottomed, hollow zone within a sand-dune system that has developed over impervious strata, sometimes due to erosion or blow-out of the dune system; its flat base level is therefore close to or at the permanent water-table level, and therefore has rich, marshy flora, with Salix species (willows) as typical woody colonisers.

Selected source glosses provide context, not a complete modern definition inventory

From Middle English slak, from Old Norse slakki (“a slope”). Cognate with Icelandic slakki, Norwegian slakke.

Relationships mentioned by the source

These are extracted mentions, not a timeline or a verified sequence of immediate parents.

Inherited-form mentionslakenm
Derivation mentionslakkinon · a slope
Cognate mentionslakkiis
Cognate mentionslakkeno

Inspect preserved source fields

Raw extraction fields are retained for auditing. Their order does not establish ancestry.

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Source etymology 5

Original entry ↗

noun

Small coal; coal dust.

Selected source glosses provide context, not a complete modern definition inventory

Of unknown origin. Possibly related to Middle Dutch slacke or Middle Low German slecke. Doublet of slag.

Relationships mentioned by the source

These are extracted mentions, not a timeline or a verified sequence of immediate parents.

Cognate mentionslackedum
Cognate mentionsleckegml
Doublet mentionslagen

Inspect preserved source fields

Raw extraction fields are retained for auditing. Their order does not establish ancestry.

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Where this record stops

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Contribute located evidence for slack →

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Imported from Wiktionary contributors; extracted by Tatu Ylonen / Wiktextract / Kaikki.org. Selected fields are reformatted and grouped; wording, source identity and etymology sections are retained. CC-BY-SA-4.0 applies to the imported source material.

Dump: 2026-10-01 · Extracted: 2026-10-30. These are snapshot dates, not the word’s first attestation or the page’s revision date.

Source entry and bibliography ↗Wiktionary revision history ↗Acquisition and rights ledger

Machine-source provenance

Source SHA-256: 5ff2c072f8099f2d2ce484bd6957bf179f046d2ad37bc36555edf8bb84cb5291
Import run: 73216b9a9b78ed3830994bf853103716f5a4dc57099e371e9f8fdc468facca26
Permanent entry ID: w-c2xhY2s