without (so much as) a by-your-leave

without (so much as) a by-your-leave

dated Without even giving notice or asking for permission. The phrase often implies that the speaker is frustrated, exasperated, or offended by what has been done. He borrows my car without so much as a by-your-leave, and I'm supposed to thank him for bringing it back in one piece? I don't think so. The four developers just up and left without a by-your-leave to go set up their own company.
See also: much, without
Farlex Dictionary of Idioms.

without (so much as) a (for or) by your leave

without (the least hint of) asking for permission. Without so much as a for or by your leave, they just walked into our house. He left, without a by your leave.
See also: by, leave, without
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

without (so much as) a ˌby your ˈleave

(old-fashioned) without asking permission; rudely: What do you think you’re doing, coming in here without so much as a by your leave?
Leave in this phrase means ‘permission’.
See also: by, leave, without
Farlex Partner Idioms Dictionary
See also:
  • without a by your leave
  • go soak your face
  • soak face
  • soak one’s face
  • (I'm) just saying
  • a slap in the face
  • torqued off
  • be torqued off
  • torque
  • a smack in the face