horn in on

horn in on (something)

To join something when one is unwelcome; to intrude or encroach. Ugh, my little brother keeps horning in on all the things I try to do with my friends.
See also: horn, on
Farlex Dictionary of Idioms.

horn in on

Intrude, join without being invited. For example, She has a rude way of horning in on our conversations. This expression alludes to an ox or bull pushing in with its horns. [c. 1900]
See also: horn, on
The American Heritage® Dictionary of Idioms by Christine Ammer.
See also:
  • horn in on (something)
  • back at it
  • back at it (again)
  • be on (one's) back
  • be on somebody's back
  • be on someone's back
  • a fire extinguisher
  • back onto
  • back onto (something)
  • a whole thing