Green’s Dictionary of Slang

anything for which one has no proper name [Dekker’s use (1604) implies a eunuch].

1604		Dekker Honest Whore Pt 1 I ii : Gods my life, hee’s a very mandrake, or else (God blesse vs) one a these whiblins, and thats woorse, and then all the children that he gets lawfully of your body sister, are bastards by a statute.
1613		Marston Insatiate Countesse II i: A rare whiblin, To be reueng’d, and yet gaine pleasure in’t .
1623		J. Taylor ‘World runnes on Wheeles’ in Works (1869) II 234: Proiects [...] of planting the Ile of Dogs with Whiblins, Corwhichets, Mushromes and Tobacco.
a.1640		R. Brome Love-sick Court V i: Come, Sir, let go your whiblin. He has yet some breath (Dis. snatcheth his sword away).