Know how to use "fewer" and "less"? Find out.
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."