1. The European wild species of cat, Felis catus (see cat n.¹ 1c); also applied to other wild animals of the cat tribe, esp. in U.S. to species of lynx. †Also plural, the skins of these used as fur.

2. figurative. Applied to a savage, ill-tempered, or spiteful person, esp. a woman: cf. cat n.¹ 2. †to run wild-cat (quot. a1652): to ‘run mad’, become demented: cf. wild adj. 12, and the attributive use at Compounds 1b below.

a. literal in sense 1: Of a wild cat.

b. figurative. Applied to banks in the western United States which, before the passing of the National Bank Act of 1863, fraudulently issued notes with little or no capital, or to their notes or transactions; hence extended to unsound or risky business enterprises generally; also to illicit businesses or their products (e.g. wild-cat whisky); and more widely to reckless, rash, or extravagant undertakings, statements, etc. (cf. wild adj. 13), and (colloquially) with reference to wildcat strikes (see Compounds 2 below).This application is said to have arisen from the fact that the notes of a bank in Michigan bore the device of a panther, locally known by the name ‘wild cat’.

wildcat drilling n. the drilling of a wildcat well.

wildcat strike n. a sudden and unofficial strike.

wildcat striker n.

wildcat stoppage n. (also wildcat walkout)

wildcat train n. U.S. an extra train running in addition to those on the timetable (see quot. 1885); occasionally elliptical; similarly wildcat engine.

wildcat well n. = sense 3c above.