Definition of keep someone/something at arm's length in English:
Avoid intimacy or close contact with someone or something.
- McNealy has long fought to keep the government at arm's length from big business and says that too much intrusion could be enough to take the fun out of being a CEO.
- He deliberately kept his sister at arm's length; what few real close friends he had you could probably count on one hand.
- She said that they still talked, but she kept him at arm's length; they were not as close.