*SET-U

English word origin

Etymology of -ious

Etymology tree Latin -iōsusbor. Latin -(i)usbor. Proto-Indo-European *-(i)yós Proto-Italic *-ijos Proto-Italic *-ios Old Latin -ios Latin -iusbor. English -ious Taken from Latin adjectives ending in -(i)ōsus (ambitious),

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In this entry · 1 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.

Unnumbered source etymology

Original entry ↗
suffix

Alternative form of -ous.

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

Etymology tree Latin -iōsusbor. Latin -(i)usbor. Proto-Indo-European *-(i)yós Proto-Italic *-ijos Proto-Italic *-ios Old Latin -ios Latin -iusbor. English -ious Taken from Latin adjectives ending in -(i)ōsus (ambitious), -(i)us (obvious) and -ius (nefarious), as well as their Romance descendants. By surface analysis, -i- + -ous.

Inspect preserved source fields

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

{
  "templates": [
    {
      "name": "ety",
      "args": {
        "1": "en",
        "2": ":bor",
        "3": "la:-ōsus<alt:-iōsus>",
        "4": "la:-us<alt:-(i)us><id:second declension>",
        "5": "la:-ius<id:suffix forming adjectives>",
        "tree": "1"
      },
      "expansion": "Etymology tree\nLatin -iōsusbor.\nLatin -(i)usbor.\nProto-Indo-European *-(i)yós\nProto-Italic *-ijos\nProto-Italic *-ios\nOld Latin -ios\nLatin -iusbor.\nEnglish -ious\n[Appendix:Glossary#loanword|Borrowed]] from\", \"terms\" : [ { \"alt\" : \"-iōsus\", \"children\" : [ ], \"lang_name\" : \"Latin\", \"term\" : \"-ōsus\", \"status\" : \"missing\", \"lang\" : \"la\" }, { \"alt\" : \"-(i)us\", \"id\" : \"second declension\", \"children\" : [ ], \"status\" : \"missing\", \"lang_name\" : \"Latin\", \"term\" : \"-us\", \"lang\" : \"la\" }, { \"id\" : \"suffix forming adjectives\", \"children\" : [ { \"terms\" : [ { \"id\" : \"suffix forming adjectives\", \"children\" : [ { \"terms\" : [ { \"id\" : \"adjective suffix\", \"children\" : [ { \"terms\" : [ { \"alt\" : \"*-ijos\", \"lang_name\" : \"Proto-Italic\", \"status\" : \"inline\", \"children\" : [ { \"terms\" : [ { \"alt\" : \"*-(i)yós\", \"children\" : [ ], \"lang_name\" : \"Proto-Indo-European\", \"term\" : \"*-yós\", \"status\" : \"ok\", \"lang\" : \"ine-pro\" } ], \"keyword_label\" : \"Inherited from\", \"keyword\" : \"inherited\" } ], \"lang\" : \"itc-pro\" } ], \"keyword_label\" : \"From\", \"keyword\" : \"from\" } ], \"status\" : \"ok\", \"lang_name\" : \"Proto-Italic\", \"term\" : \"*-ios\", \"lang\" : \"itc-pro\" } ], \"keyword_label\" : \"Inherited from\", \"keyword\" : \"inherited\" } ], \"status\" : \"ok\", \"lang_name\" : \"Old Latin\", \"term\" : \"-ios\", \"lang\" : \"itc-ola\" } ], \"keyword_label\" : \"From\", \"keyword\" : \"from\" } ], \"status\" : \"ok\", \"lang_name\" : \"Latin\", \"term\" : \"-ius\", \"lang\" : \"la\" } ], \"keyword\" : \"bor\" } ], \"lang_name\" : \"English\", \"term\" : \"-ious\", \"status\" : \"ok\", \"lang\" : \"en\" }\" data-lang=\"en\" data-title=\"-ious\">"
    },
    {
      "name": "surf",
      "args": {
        "1": "en",
        "2": "-i-",
        "3": "-ous"
      },
      "expansion": "By surface analysis, -i- + -ous"
    },
    {
      "name": "ety",
      "args": {
        "1": "en",
        "2": ":bor",
        "3": "la:-ōsus<alt:-iōsus>",
        "4": "la:-us<alt:-(i)us><id:second declension>",
        "5": "la:-ius<id:suffix forming adjectives>",
        "tree": "1"
      },
      "expansion": "Etymology tree\nProto-Indo-European *h₃ed-\nProto-Indo-European *-os\nProto-Indo-European *h₃édosder.?\nProto-Italic *-ŏ̄dsos?\nOld Latin -ōssus\nLatin -iōsusbor.\nProto-Indo-European *-ós\nProto-Indo-European *-os\nProto-Indo-European *-ós\nProto-Indo-European *-ós\nProto-Indo-European *-ós\nProto-Indo-European *-ós\nProto-Indo-European *-os\nProto-Italic *-os\nArchaic Latin -os\nLatin -(i)usbor.\nProto-Indo-European *-(i)yós\nProto-Italic *-ijos\nProto-Italic *-ios\nOld Latin -ios\nLatin -iusbor.\nEnglish -ious"
    }
  ],
  "links": [
    [
      "-iōsus",
      "-osus#Latin"
    ],
    [
      "-(i)us",
      "-us#Latin:_second_declension"
    ],
    [
      "*-(i)yós",
      "Reconstruction:Proto-Indo-European/-yós"
    ],
    [
      "*-ios",
      "Reconstruction:Proto-Italic/-ios#Proto-Italic:_adjective_suffix"
    ],
    [
      "-ios",
      "-ios#Latin:_suffix_forming_adjectives"
    ],
    [
      "-ius",
      "-ius#Latin:_suffix_forming_adjectives"
    ],
    [
      "-(i)ōsus",
      "-osus#Latin"
    ],
    [
      "ambitious",
      "ambitious#English"
    ],
    [
      "-(i)us",
      "-us#Latin:_second_declension"
    ],
    [
      "obvious",
      "obvious#English"
    ],
    [
      "-ius",
      "-ius#Latin:_suffix_forming_adjectives"
    ],
    [
      "nefarious",
      "nefarious#English"
    ],
    [
      "-i-",
      "-i-#English"
    ],
    [
      "-ous",
      "-ous#English"
    ]
  ],
  "references": [],
  "descendants": [],
  "lexical": [
    {
      "pos": "suffix",
      "glosses": [
        "Alternative form of -ous."
      ],
      "tags": [
        "alt-of",
        "alternative",
        "morpheme"
      ],
      "recordId": "152fbbef4fb385286478ccd4f63255e344eb8b1f9943f5ece3308d814372dc3c",
      "rawRecordSha256": "e0ca48b4a61908ec726793c7e6b9637a2c312ec331e0cd52c07e7cadd2bf08bb",
      "sourceRecordOrdinal": 1477074
    }
  ],
  "omittedAuxiliaryFields": {
    "templates": 0,
    "links": 0,
    "references": 0,
    "descendants": 0,
    "lexicalRecords": 0,
    "lexicalSenses": 0,
    "glosses": 0
  }
}

Where this record stops

This page does not supply an independently verified sound-change sequence, first-use manuscript or complete family tree unless a cited analysis explicitly establishes one. Missing detail here is a limit of this record—not a claim that humanity knows nothing more.

An older meaning does not determine what a word must mean today. Follow the sources, preserve disagreements, and keep ancestry separate from interpretation.

Contribute located evidence for -ious →

Source and snapshot

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-LWlvdXM