straight from the horse’s mouth

(straight) from the horse's mouth

From the original or most reliable source. A: "Is our test really getting rescheduled?" B: "Yep, our teacher was ahead of me in the lunch line, so I heard it straight from the horse's mouth."
See also: mouth
Farlex Dictionary of Idioms.

straight from the horse’s mouth

mod. directly from the source, not just a horse. (As if a racehorse were giving racing tips.) This came straight from the horse’s mouth. It’s Zeerocks Copy in the sixth race.
See also: mouth, straight
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • (straight) from the horse's mouth
  • from the horse's mouth
  • the horse's mouth
  • hear (something) straight from the horse's mouth
  • get (something) straight from the horse's mouth
  • get straight from the horse's mouth
  • that's the bunny
  • tick
  • bend over, here it comes again
  • BOHICA