"frightener" meaning in English

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "frighten",
        "3": "er",
        "id2": "agent noun"
      },
      "expansion": "frighten + -er",
      "name": "suffix"
    }
  ],
  "etymology_text": "From frighten + -er.",
  "forms": [
    {
      "form": "frighteners",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "frightener (plural frighteners)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English terms suffixed with -er (agent noun)",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        }
      ],
      "form_of": [
        {
          "extra": "one who, or that which, frightens",
          "word": "frighten"
        }
      ],
      "glosses": [
        "Agent noun of frighten: one who, or that which, frightens."
      ],
      "id": "en-frightener-en-noun-Bht7-Z9r",
      "links": [
        [
          "frighten",
          "frighten#English"
        ]
      ],
      "related": [
        {
          "word": "put the frighteners on someone"
        }
      ],
      "tags": [
        "agent",
        "form-of"
      ]
    }
  ],
  "word": "frightener"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "frighten",
        "3": "er",
        "id2": "agent noun"
      },
      "expansion": "frighten + -er",
      "name": "suffix"
    }
  ],
  "etymology_text": "From frighten + -er.",
  "forms": [
    {
      "form": "frighteners",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "frightener (plural frighteners)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "put the frighteners on someone"
    }
  ],
  "senses": [
    {
      "categories": [
        "English agent nouns",
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English nouns",
        "English terms suffixed with -er (agent noun)",
        "Pages with 1 entry"
      ],
      "form_of": [
        {
          "extra": "one who, or that which, frightens",
          "word": "frighten"
        }
      ],
      "glosses": [
        "Agent noun of frighten: one who, or that which, frightens."
      ],
      "links": [
        [
          "frighten",
          "frighten#English"
        ]
      ],
      "tags": [
        "agent",
        "form-of"
      ]
    }
  ],
  "word": "frightener"
}