so's your old man

so's your old man

dated A childish, petty response to an insult, essentially meaning "same to you." "Old man" refers to one's father. A: "You're a stupid monkey brain!" B: "Oh yeah? Well, so's your old man!"
See also: man, old
Farlex Dictionary of Idioms.

so's your old man

Inf. The same to you!; Drop dead! (old. A catch phrase indicating basic disagreement or hostility.) Bill: You're acting like an idiot! Tom: So's your old man! I don't know what you said, but so's your old man!
See also: man, old
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

So’s your old man!

exclam. The same to you!; Drop dead! (Indicates basic disagreement or hostility.) BILL: You’re acting like an idiot! TOM: So’s your old man! I don’t know what you said, but so’s your old man!
See also: old
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions

So's your old man

The same to you, buddy! Casting another's parent (the “Yo Mama” jokes) or parentage (“you son of a bitch!”) in an unfavorable light has always been part of popular speech. “So's your old man!” is no more than a comeback that is used when (1) you don't want to provoke your antagonist very much or (2) you can't think of a more clever rejoinder. You might have said “Aw, your mother wears combat boots,” which, before women served in combat in the military, implied that she was less than feminine. That was a dangerous thing to do: fathers and other male relatives were fair game, but the female side of the family, and especially one's mother, was out of bounds before “Yo Mama” jokes crossed that boundary.
See also: man, old
Endangered Phrases by Steven D. Price
See also:
  • So’s your old man!
  • so's your old lady
  • I know you are but what am I?
  • have (one's) monkey up
  • have your monkey up
  • pudding and tame
  • get (one's) monkey up
  • put (one's) monkey up
  • monkey business
  • have got a monkey on (one's) back
References in periodicals archive
The "so's your old man" school of persuasion may still work on the playground, but there's no place for it among Illinois legislators.
'Death wish' remark deserves strong, bipartisan rebuke
Silent films were remade as talkies (So's Your Old Man remade as You're Telling Me!, and the theatrical version of Poppy remade as Sally of the Sawdust and remade yet again as the film Poppy), vaudeville sketches as interludes within broader narratives (Six of a Kind, The Old Fashioned Way); many of the stories themselves take place within a not-so-distant past.
Notes on W.C. Fields (for Jim Gardner)
In his first film, "So's Your Old Man," he played W.C.
OBITUARIES
The "so's your old man" school of persuasion may still work on the playground, but there's no place for it among Illinois legislators -- no matter how much public discourse has become degraded in an era tainted by online trolls and a U.S.
Offensive, counterproductive Even with apology, lawmaker's 'death wish' remark deserves strong rebuke