A design, action, or decision that is clearly incorrect or inappropriate. Often capitalised; always emphasised in speech as if capitalised. The opposite of the Right Thing; more generally, anything that is not the Right Thing. In cases where "the good is the enemy of the best", the merely good - although good - is nevertheless the Wrong Thing. "In C, the default is for module-level declarations to be visible everywhere, rather than just within the module. This is clearly the Wrong Thing."
We live in a washed-out PC world where nobody in government wants to say the wrong thing so they say nothing at all.
I was [making the offer] because building a mosque was the wrong thing to do at the wrong location at the wrong time….
There have been a few incidents in basketball where saying the wrong thing ended up costing people jobs.