"brainer" meaning in English

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "brain",
        "3": "-er",
        "id2": "relational"
      },
      "expansion": "brain + -er",
      "name": "af"
    }
  ],
  "etymology_text": "From brain + -er.",
  "forms": [
    {
      "form": "brainers",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "brainer (plural brainers)",
      "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 (relational)",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "someone with a certain type of brain"
      ],
      "id": "en-brainer-en-noun-Q5zdh~1y",
      "links": [
        [
          "brain",
          "brain"
        ]
      ],
      "raw_glosses": [
        "(only used in combinations) someone with a certain type of brain"
      ],
      "raw_tags": [
        "used in combinations"
      ],
      "related": [
        {
          "word": "no-brainer"
        },
        {
          "word": "left-brainer"
        },
        {
          "word": "right-brainer"
        },
        {
          "word": "yes-brainer"
        }
      ]
    }
  ],
  "sounds": [
    {
      "rhymes": "-eɪnə(ɹ)"
    }
  ],
  "word": "brainer"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "brain",
        "3": "-er",
        "id2": "relational"
      },
      "expansion": "brain + -er",
      "name": "af"
    }
  ],
  "etymology_text": "From brain + -er.",
  "forms": [
    {
      "form": "brainers",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "brainer (plural brainers)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "no-brainer"
    },
    {
      "word": "left-brainer"
    },
    {
      "word": "right-brainer"
    },
    {
      "word": "yes-brainer"
    }
  ],
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English nouns",
        "English terms suffixed with -er (relational)",
        "Pages with 1 entry",
        "Pages with entries",
        "Rhymes:English/eɪnə(ɹ)",
        "Rhymes:English/eɪnə(ɹ)/2 syllables"
      ],
      "glosses": [
        "someone with a certain type of brain"
      ],
      "links": [
        [
          "brain",
          "brain"
        ]
      ],
      "raw_glosses": [
        "(only used in combinations) someone with a certain type of brain"
      ],
      "raw_tags": [
        "used in combinations"
      ]
    }
  ],
  "sounds": [
    {
      "rhymes": "-eɪnə(ɹ)"
    }
  ],
  "word": "brainer"
}