Worst, v. t. [imp. & p. p. Worsted; p. pr. & vb. n. Worsting.]
Etymology: [See Worse, v. t. & a.]
To gain advantage over, in contest or competition; to get the better of; to defeat; to overthrow; to discomfit. The . . . Philistines were worsted by the captivated ark. South.
3 other Webster entries under this spelling
Worst, a., superl. of Bad.
Bad, evil, or pernicious, in the highest degree, whether in a physical or moral sense. See Worse. "Heard so oft in worst extremes." Milton. I have a wife, the worst that may be. Chaucer. If thou hadst not been born the worst of men, Thou hadst been a knave and flatterer. Shak.
Worst, n.
That which is most bad or evil; the most severe, pernicious, calamitous, or wicked state or degree. The worst is not So long as we can say, This is the worst. Shak. He is always sure of finding diversion when the worst comes to the worst. Addison.
Worst, v. i.
To grow worse; to deteriorate. [R.] "Every face . . . worsting." Jane Austen.
Shades of meaning
Fernald has no entry of its own for worst; he lists it under beat, conquer.
He lists it without comment; the entries above explain its neighbors.