a bad taste in the mouth

a bad taste in (one's)/the mouth

A negative impression (based on something that has already happened). I don't know, man, the fact that he lied to you just leaves a bad taste in my mouth.
See also: bad, mouth, taste
Farlex Dictionary of Idioms.

a bad (or bitter or nasty) taste in the (or someone's) mouth

a strong feeling of distress or disgust following an experience. informal
See also: bad, mouth, taste
Farlex Partner Idioms Dictionary
See also:
  • a bad taste in (one's)/the mouth
  • in bad taste
  • so bad (that) (one) can taste it
  • so bad one can taste it
  • a bad press
  • bad press
  • in (someone's) bad books
  • in someone's bad books
  • have a bad opinion of (someone or something)
  • have a good, bad, high, low, etc. opinion of somebody/something
References in periodicals archive
That attitude might have gone down well when Arthur Guinness first began brewing the black stuff back in 1759, but in this age of equality it merely leaves a bad taste in the mouth.
Voice Of The Irish Daily Mirror: Brewing up a storm
"But the whole thing leaves a bad taste in the mouth, especially as we paid for an operation for him at the start of this season and looked after him."
Football: Arkins saga worries Ron