backform

Alternative form of back-form (“a back-formation”).

I agree 100%, but I feel compelled, as if by a spot of bad beef, to point out that "gruntled" is a real word and listed in many better dictionaries. Its use is either archaic (in which case it means the same as "disgruntled", but is less emphatic) or recent (in which case it's a backform that means the opposite of "disgruntled"). I had an office mate who regularly used "gruntled", so this came up now and then.

What's improper about it? backforms are shorter than their sources. When is misanalyzed as , the backform results.

Alternative form of back-form.

Pennanen (1966: 150) also commented on the relative productiveness of British and American English in backforming new words: Although the coining of back-formations is at present mainly carried on in America on the various levels of spoken and written usage, it should be emphasized that the difference here is one of degree only.

Those who deny the synchronic relevance of backformation would hold that backforming x from y is simply the folk-etymological assumption that x is the derivational source of y.