"lean and mean" meaning in Inglese

{
  "categories": [
    {
      "kind": "other",
      "name": "Espressioni in inglese",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "Parole in inglese",
      "parents": [],
      "source": "w"
    }
  ],
  "lang": "Inglese",
  "lang_code": "en",
  "pos": "phrase",
  "pos_title": "Espressione",
  "senses": [
    {
      "glosses": [
        "molto ambizioso"
      ],
      "id": "it-lean_and_mean-en-phrase-S9XUjgPf",
      "raw_tags": [
        "US"
      ]
    }
  ],
  "word": "lean and mean"
}

{
  "categories": [
    "Espressioni in inglese",
    "Parole in inglese"
  ],
  "lang": "Inglese",
  "lang_code": "en",
  "pos": "phrase",
  "pos_title": "Espressione",
  "senses": [
    {
      "glosses": [
        "molto ambizioso"
      ],
      "raw_tags": [
        "US"
      ]
    }
  ],
  "word": "lean and mean"
}