an object lesson

an object lesson

An actual, concrete example of something. Your overreaction was an object lesson in how to ensure that your kids don't tell you the truth.
See also: lesson, object
Farlex Dictionary of Idioms.

an ˈobject lesson

a practical example of what you should or should not do in a particular situation: It was an object lesson in how not to make a speech. He did absolutely everything wrong.An object lesson was a school lesson that used real objects as a way of teaching in a very direct and practical way.
See also: lesson, object
Farlex Partner Idioms Dictionary
See also:
  • lesson
  • That’ll teach someone
  • that'll teach
  • that'll teach (one) ((not) to do something)
  • pack up
  • have (one's)/the facts straight
  • confuse
  • confuse (someone or something) with (someone or something)
  • confuse or an animal with
  • confuse with
References in classic literature
The collection, I assure you, was an object lesson in human malignity.
May I relate the idyl of your tragic passion, dear Dubois, as an object lesson?"
All this is used up; it is no longer instructive as an object lesson in revolutionary anarchism.
Yet what has happened since is an object lesson in the difficulties of entrenching reform, let alone building on it.
Roadworks on Shrewsbury's Pride Hill, that have taken place during the past year, have provided an object lesson in how not to run a civil engineering project.
Son seems to thrive on the responsibility, and in adversity when Kane (left) is out - and his hunger to succeed is an object lesson for youngsters.
SWANSEA CITY look like an object lesson in how to sell yourself down the river.
An object lesson: leave the expert work to the experts.
Duxbury cites Kilmuir as an object lesson in why one should be careful about labeling people.
During his speech, yhsanoy-lu said Medymak Hotel should be turned into a museum as an object lesson for the people.
LUIS SUAREZ While Gareth Bale was providing an object lesson in how to be a footballing role model, Uruguay's Suarez, below, was showing exactly below how not to do it with his third on-field biting incident.
With all the facts that are coming into the public domain now, it's an object lesson in Why politicians should wait for the evidence before devising election strategies.
Those seeking an object lesson in the relative value of art and commerce in Hollywood need look no further than Ethan Hawke, who kicked off the summer movie season with Richard Linklater's "Before Midnight" and now brings it to a close with "Getaway," another tale of an American expat winding his way through an exotic foreign locale.
The Reyhanli incident should be an object lesson for Turkey and reactionary states in the region to stop supporting terrorists, the Iranian legislator stated.
WHAT an object lesson in double standards our city council is portraying.