• (RP, America) IPA: /ɡɹaʊs/
• (Australia) IPA: /ɡræɔs/
• (New Zealand) IPA: /ɡræus/

Attested in the 1530s, as grows "moorhen", a plural used collectively.

The origin of the noun is unknown; the following derivations have been suggested:

• From Old French grue (modern French grue) or Medieval Latin gruta, both from Latin grūs, ultimately from Proto-Indo-European *gerh₂-.
• Borrowed from Celtic or a different Medieval Latin - word.
• Imitative of the bird’s call.

  The verb is derived from the noun.

grouse

1. (countable) Any of various game birds of the subfamily Tetraoninae which inhabit temperate and subarctic regions of the Northern Hemisphere; specifically, the red grouse (Lagopus lagopus scotica) native to heather moorland on the British Isles. [from 1530s]

   (red grouse) Synonyms: moorbird, moorcock, moorfowl

   • 1633 (first performance), Benjamin Jonson [i.e., Ben Jonson], “A Tale of a Tub. A Comedy […]”, in The Workes of Benjamin Jonson. The Second Volume. […] (Second Folio), London: […] Richard Meighen, published 1640, →OCLC ↗, Act II, scene i, page 70 ↗:

     Looke to 't, young growſe: Ile lay it on, and ſure; / Take 't off who's wull.

     Used as an insult.

2. (uncountable) The flesh or meat of this bird eaten as food.

• French: coq de bruyère
• German: Raufußhuhn
• Italian: gallo cedrone, pernice, urogallo
• Portuguese: tetraz, galo-silvestre
• Russian: ря́бчик
• Spanish: tetraónino, urogallo

grouse (grouses, present participle grousing; simple past and past participle groused)

1. (intransitive) To hunt or shoot grouse.

The origin of the verb is uncertain; it is possibly borrowed from nrf groucier, from Old French groucier, grousser [and other forms] (whence grutch and grouch).

The noun is derived from the verb.

grouse (grouses, present participle grousing; simple past and past participle groused)

1. (intransitive, originally, military slang, informal) To complain or grumble. [from late 19th c.]
   • 1890, Kipling, The Young British Soldier:

     If you're cast for fatigue by a sergeant unkind,
     Don't grouse like a woman, nor crack on, nor blind;
     Be handy and civil, and then you will find
     That it's beer for the young British soldier.

   • 1925 July – 1926 May, A[rthur] Conan Doyle, “(please specify the chapter number)”, in The Land of Mist (eBook no. 0601351h.html), Australia: Project Gutenberg Australia, published April 2019:

     Grouse away!" he growled. "If grousin' made a man happy, you'd be the champion."

• German: murren, grummeln
• Italian: brontolare, lamentarsi
• Spanish: quejarse

grouse (plural grouses)

1. (informal) A cause for complaint; a grumble. [from early 20th c.]

grouse (comparative grouser, superlative grousest)

1. (Australian, NZ, slang) Excellent. [from 1920s]

   Synonyms: Thesaurus:excellent

   Antonyms: Thesaurus:bad

   I had a grouse day.    That food was grouse.

   • 1965, Mudrooroo, Wild Cat Falling, HarperCollins, published 2001, page 99:

     Real grouse birthday this. First time he's had a party.