Keep themselves to themselves mostly,…

（たいていは群れ以外の奴らを寄せ付けねぇ。）
　『Harry Potter and the Philosopher's Stone』（ハリーポッターと賢者の石）より。ケンタウロスについてハーマイオニーに説明するハグリッドのセリフ。

• "keep oneself to oneself" が成句。「ひとりぼっちでいる／付き合いを避ける」という意味に（to remain aloof ※aloof：打ち解けない／to live a very quiet private life and not do many things that involve other people／to stay apart from other people／to avoid other people／ to avoid meeting people socially or becoming involved in their affairs）。
  • He does tend to keep himself to himself.
  • Keep yourself to yourself, and you'll be all right there.
  • He's a very private person - he keeps himself to himself.
• "keep to oneself" だけでも同じ意味で使える。"keep oneself to oneself"のほうが英国的用法というだけの違いみたい。ハリポタ米国版は "keep to themselves" になってるのかな。見てみたいな。
  • Ann tends to keep to herself. She doesn't have many friends.
  • I try to keep to myself each morning so I can get some work done.
  • She was a shy girl who kept pretty much to herself.
  • Nobody knows much about him; he keeps very much to himself.

（Philosopher's Stoneがイギリス版、Sorcerer's Stoneがアメリカ版。）
（kindle読みがものすごくはかどっておすすめ。）