keep somebody at arm's length

keep (one) at arm's length

To keep one a certain distance away, either physical or figurative, in order to afford a level of safety or security or to prevent intimacy. John always keeps his friends at arm's length, so that no one gets close enough to hurt his feelings. My daughter likes to watch me cook, but I make sure to keep her at arm's length so she doesn't get close to anything hot.
See also: keep, length
Farlex Dictionary of Idioms.

keep somebody at arm’s ˈlength

avoid becoming too friendly with somebody: He’s the kind of man who’s best kept at arm’s length.
See also: keep, length, somebody
Farlex Partner Idioms Dictionary
See also:
  • keep (one) at arm's length
  • keep someone at arm's length
  • keep someone or something at arm's length
  • hold (one) at arm's length
  • hold (one) at a distance
  • hold (one) at a comfortable distance
  • at arm's length
  • let off on
  • let off on (someone or something)
  • be as good as dead