Wild-cat \Wild"-cat`\, a.

1. Unsound; worthless; irresponsible; unsafe; -- said to have been originally applied to the notes of an insolvent bank in Michigan upon which there was the figure of a panther. [1913 Webster]

2. (Railroad) Running without control; running along the line without a train; as, a wild-cat locomotive. [1913 Webster] [1913 Webster]

Source: The Collaborative International Dictionary of English v.0.48
 

66 Moby Thesaurus words for "wildcat": Jezebel, Leo, Siberian tiger, adventurous, aleatory, beldam, bitch-kitty, bobcat, cat-a-mountain, catamount, chancy, cheetah, cougar, dicey, disobedient, full of risk, fury, grimalkin, hag, hazardous, headstrong, heady, hellcat, hellhag, insubordinate, irresponsible, jaguar, lawless, leopard, licentious, lion, lynx, mountain lion, mutinous, ocelot, painter, panther, puma, rampant, reinless, riskful, risky, self-willed, she-devil, she-wolf, simba, siren, speculative, termagant, tiger, tigress, unaccountable, unbridled, unchecked, uncontrolled, uncurbed, undisciplined, ungoverned, unreined, unrestrained, venturesome, venturous, virago, vixen, willful, witch

Source: Moby Thesaurus II by Grady Ward, 1.0
 

wildcat adj
1: outside the bounds of legitimate or ethical business practices; "wildcat currency issued by irresponsible banks"; "wildcat stock speculation"; "a wildcat airline"; "wildcat life insurance schemes"
2: without official authorization; "an unauthorized strike"; "wildcat work stoppage" [syn: unauthorized, unauthorised]
3: (of a mine or oil well) drilled speculatively in an area not known to be productive; "drilling there would be strictly a wildcat operation"; "a wildcat mine"; "wildcat drilling"; "wildcat wells"

noun

1: an exploratory oil well drilled in land not known to be an oil field [syn: wildcat well]
2: a cruelly rapacious person [syn: beast, wolf, savage, brute]
3: any small or medium-sized cat resembling the domestic cat and living in the wild [also: wildcatting, wildcatted]

Source: WordNet (r) 2.0
 

Wild-cat \Wild"-cat`\, a.

1. Unsound; worthless; irresponsible; unsafe; -- said to have been originally applied to the notes of an insolvent bank in Michigan upon which there was the figure of a panther.

2. (Railroad) Running without control; running along the line without a train; as, a wild-cat locomotive.

Source: Webster's Revised Unabridged Dictionary (1913)