"knuckle duster" meaning in Anglais

{
  "categories": [
    {
      "kind": "other",
      "name": "Compositions en anglais",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Locutions nominales en anglais",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Anglais",
      "orig": "anglais",
      "parents": [],
      "source": "w"
    }
  ],
  "etymology_texts": [
    "Composé de knuckle (« jointure ») et de duster, du nom de Steve K. Robins Duster."
  ],
  "lang": "Anglais",
  "lang_code": "en",
  "pos": "noun",
  "pos_title": "Locution nominale",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Lexique en anglais de l’armement",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Wiktionnaire:Exemples manquants en anglais",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Anglais du Royaume-Uni",
          "orig": "anglais du Royaume-Uni",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Anglais d’Australie",
          "orig": "anglais d’Australie",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Coup-de-poing américain."
      ],
      "id": "fr-knuckle_duster-en-noun-o7BtPp5T",
      "raw_tags": [
        "Armement",
        "Royaume-Uni",
        "Australie"
      ]
    }
  ],
  "synonyms": [
    {
      "raw_tags": [
        "États-Unis"
      ],
      "word": "brass knuckle"
    }
  ],
  "word": "knuckle duster"
}

{
  "categories": [
    "Compositions en anglais",
    "Locutions nominales en anglais",
    "anglais"
  ],
  "etymology_texts": [
    "Composé de knuckle (« jointure ») et de duster, du nom de Steve K. Robins Duster."
  ],
  "lang": "Anglais",
  "lang_code": "en",
  "pos": "noun",
  "pos_title": "Locution nominale",
  "senses": [
    {
      "categories": [
        "Lexique en anglais de l’armement",
        "Wiktionnaire:Exemples manquants en anglais",
        "anglais du Royaume-Uni",
        "anglais d’Australie"
      ],
      "glosses": [
        "Coup-de-poing américain."
      ],
      "raw_tags": [
        "Armement",
        "Royaume-Uni",
        "Australie"
      ]
    }
  ],
  "synonyms": [
    {
      "raw_tags": [
        "États-Unis"
      ],
      "word": "brass knuckle"
    }
  ],
  "word": "knuckle duster"
}