wildcat

a cruelly rapacious person

an exploratory oil well drilled in land not known to be an oil field

without official authorization

“wildcat work stoppage”

any small or medium-sized cat resembling the domestic cat and living in the wild

drilled speculatively in an area not known to be productive

“drilling there would be strictly a wildcat operation”

outside the bounds of legitimate or ethical business practices

“wildcat currency issued by irresponsible banks”