Wiktionary
onliest
a. (context informal and dialectal English) (en-superlativeonly) alt. (context informal and dialectal English) (en-superlativeonly)
Usage examples of "onliest".
My ma an her chillen wuz the onliest slaves my marster and mistis had.
The onliest ones that stayed are us that are too old to make it over the grade and some of the merchants who stayed here to supply those that went.
The trouble is, the onliest one around here that knows that too, is the wrong one.
But the fucking stuff smells like vinegar and tastes like cat puke and the onliest one really liked it was Simon, so I never lifted any more of it.
Peggy must of thought she was the one and onliest elephant on dis earth.