*SET-U

English word origin

Etymology of wacko

Etymology tree English whack Proto-Indo-European *-kos Proto-Germanic *-gaz Proto-West Germanic *-g Old English -iġ Middle English -y English -y English wack(y) Latin ō Old French ohbor. Middle English o English O ▲ Midd

1 source sectionExtended source reportWiktionary original ↗
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 ↗
intj

Hurrah!

adj

Amusingly eccentric or irrational.

noun

An amusingly eccentric or irrational person.

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

Etymology tree English whack Proto-Indo-European *-kos Proto-Germanic *-gaz Proto-West Germanic *-g Old English -iġ Middle English -y English -y English wack(y) Latin ō Old French ohbor. Middle English o English O ▲ Middle English o English oh English -o English wacko From wack(y) + -o.

Inspect preserved source fields

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

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        "1": "en",
        "2": ":af",
        "3": "wacky<alt:wack(y)>",
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        "text": "+",
        "tree": "1"
      },
      "expansion": "Etymology tree\nEnglish whack\nProto-Indo-European *-kos\nProto-Germanic *-gaz\nProto-West Germanic *-g\nOld English -iġ\nMiddle English -y\nEnglish -y\nEnglish wack(y)\nLatin ō\nOld French ohbor.\nMiddle English o\nEnglish O\n▲\nMiddle English o\nEnglish oh\nEnglish -o\nEnglish wacko\n[Appendix:Glossary#inherited|Inherited]] from\", \"keyword\" : \"inherited\" } ], \"status\" : \"ok\", \"lang_name\" : \"Proto-Germanic\", \"term\" : \"*-gaz\", \"lang\" : \"gem-pro\" } ], \"keyword_label\" : \"Inherited from\", \"keyword\" : \"inherited\" } ], \"status\" : \"ok\", \"lang_name\" : \"Proto-West Germanic\", \"term\" : \"*-g\", \"lang\" : \"gmw-pro\" } ], \"keyword_label\" : \"Inherited from\", \"keyword\" : \"inherited\" } ], \"status\" : \"ok\", \"lang_name\" : \"Old English\", \"term\" : \"-iġ\", \"lang\" : \"ang\" } ], \"keyword_label\" : \"Inherited from\", \"keyword\" : \"inherited\" } ], \"status\" : \"ok\", \"lang_name\" : \"Middle English\", \"term\" : \"-y\", \"lang\" : \"enm\" } ], \"keyword_label\" : \"Inherited from\", \"keyword\" : \"inherited\" } ], \"status\" : \"ok\", \"lang_name\" : \"English\", \"term\" : \"-y\", \"lang\" : \"en\" } ], \"keyword_label\" : \"From\", \"is_group\" : true, \"keyword\" : \"affix\" } ], \"lang_name\" : \"English\", \"term\" : \"wacky\", \"status\" : \"ok\", \"lang\" : \"en\" }, { \"children\" : [ { \"terms\" : [ { \"id\" : \"vocative\", \"children\" : [ { \"terms\" : [ { \"id\" : \"oh\", \"children\" : [ { \"keyword_abbrev\" : \"bor.\", \"keyword_label\" : \"Borrowed from\", \"terms\" : [ { \"children\" : [ { \"terms\" : [ { \"id\" : \"vocative\", \"children\" : [ ], \"status\" : \"ok\", \"lang_name\" : \"Latin\", \"term\" : \"ō\", \"lang\" : \"la\" } ], \"keyword_label\" : \"Inherited from\", \"keyword\" : \"inherited\" } ], \"lang_name\" : \"Old French\", \"term\" : \"oh\", \"status\" : \"inline\", \"lang\" : \"fro\" } ], \"keyword\" : \"bor\" } ], \"status\" : \"ok\", \"lang_name\" : \"Middle English\", \"term\" : \"o\", \"lang\" : \"enm\" } ], \"keyword_label\" : \"Inherited from\", \"keyword\" : \"inherited\" } ], \"status\" : \"ok\", \"lang_name\" : \"English\", \"term\" : \"O\", \"lang\" : \"en\" }, { \"id\" : \"surprise\", \"children\" : [ { \"terms\" : [ { \"is_duplicate\" : true, \"children\" : [ ], \"id\" : \"oh\", \"status\" : { \"1\" : \"enm\", \"2\" : \":bor\", \"3\" : \"fro:oh<ety:inh<la:ō<id:vocative>>>\", \"id\" : \"oh\" }, \"lang_name\" : \"Middle English\", \"term\" : \"o\", \"lang\" : \"enm\" } ], \"keyword_label\" : \"Inherited from\", \"keyword\" : \"inherited\" } ], \"status\" : \"ok\", \"lang_name\" : \"English\", \"term\" : \"oh\", \"lang\" : \"en\" } ], \"keyword_label\" : \"From\", \"keyword\" : \"from\" } ], \"lang_name\" : \"English\", \"term\" : \"-o\", \"status\" : \"ok\", \"lang\" : \"en\" } ], \"keyword_label\" : \"From\", \"is_group\" : true, \"keyword\" : \"affix\" } ], \"lang_name\" : \"English\", \"term\" : \"wacko\", \"status\" : \"ok\", \"lang\" : \"en\" }\" data-lang=\"en\" data-title=\"wacko\">\nFrom wack(y) + -o."
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    ],
    [
      "*-gaz",
      "Reconstruction:Proto-Germanic/-gaz#Proto-Germanic:_adjectives"
    ],
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      "*-g",
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    ],
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    ],
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    ]
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  "lexical": [
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      "pos": "intj",
      "glosses": [
        "Hurrah!"
      ],
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        "dated"
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        "Amusingly eccentric or irrational."
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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 wacko →

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-d2Fja28