If the most unfavorable or injurious circumstances should occur. This term would make more sense as if worse comes to worst (comparative to superlative), but it has been used in its present form since the late sixteenth century. It generally is followed by some expedient solution, as in “If worst comes to worst he’ll declare bankruptcy.” The Restoration dramatists had fun with it. John Dryden said (Sir Martin Mar-All, 1667), “If worst comes to the worst, he leaves you an honest woman,” and William Congreve (The Way of the World, 1700) wrote, “If the worst comes to the worst, I’ll turn my wife to grass.”