a bad teacher who after all proved to be a good teacher
because some of the students have thought "I will never become such a person" |
|
I believe your focus is that the teacher was "good"
only insofar as
he provided an example of what not to do if you wanted to be a good
teacher -- not that the teacher was ever really a good teacher or ever
really came to be seen as a good teacher.
Furthermore, you want an adjectival form that expresses this example of what not to do.
That's a tough assignment.
(only) by negative example comes to mind (
The teacher was good only by [providing a] negative example.),
but is unsatisfactory in many ways. I don't think there is such a
word in English. The idea may have to be expressed in a different
way.
cautionary tale is another phrase that comes to mind, but a simple substitution in the form
*a cautionary tale teacher absolutely will not work.
object lesson is similar in meaning, but has the same problem. You'd have to say something like
His teaching technique was a [cautionary tale / object lesson] in bad teaching.
In the final analysis, if I had to choose, I would translate
an other-way-round [teacher / parent / boss / ...] as
a perfect example of a bad [teacher / parent / boss / ...]. For
a bad you might substitute
an incompetent.
He was an inspiration to his students (only) in being a perfect example of [a bad / an incompetent ] teacher.
CJ