"fool to oneself" meaning in English

{
  "forms": [
    {
      "form": "fools to themselves",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "fools to themselves"
      },
      "expansion": "fool to oneself (plural fools to themselves)",
      "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": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "text": "By swimming, drunk, late at night and alone, he was being a fool to himself.",
          "type": "example"
        }
      ],
      "glosses": [
        "One who knowingly makes a decision or takes an action that is to their own disadvantage."
      ],
      "id": "en-fool_to_oneself-en-noun-RZDYgyCc",
      "links": [
        [
          "knowingly",
          "knowingly"
        ],
        [
          "decision",
          "decision"
        ],
        [
          "disadvantage",
          "disadvantage"
        ]
      ]
    }
  ],
  "word": "fool to oneself"
}

{
  "forms": [
    {
      "form": "fools to themselves",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "fools to themselves"
      },
      "expansion": "fool to oneself (plural fools to themselves)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with usage examples",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "examples": [
        {
          "text": "By swimming, drunk, late at night and alone, he was being a fool to himself.",
          "type": "example"
        }
      ],
      "glosses": [
        "One who knowingly makes a decision or takes an action that is to their own disadvantage."
      ],
      "links": [
        [
          "knowingly",
          "knowingly"
        ],
        [
          "decision",
          "decision"
        ],
        [
          "disadvantage",
          "disadvantage"
        ]
      ]
    }
  ],
  "word": "fool to oneself"
}