wildcat

Of or concerning businesses operating outside standard or legitimate practice.

Of or concerning actions undertaken by workers without approval or in defiance of the formal leadership of their trade unions.

Unauthorized by the proper authorities.

(old-fashioned) Of or concerning irresponsible banks or banking, (particularly) small, independent operations.

Of or concerning oil exploration in new areas, (particularly) small, independent operations.

Of or concerning customized or hand-made cartridges.

A cat that lives in the wilderness.

Felis silvestris, a common small Old World wild cat somewhat larger than a house cat.

(US) A bobcat (Lynx rufus) or other similar New World species of lynx.

Any feral cat.

Clipping of wildcat strike (“a strike undertaken without authorization from the relevant trade union”).

(informal, figurative) A person who acts like a wildcat, (usually) a violent and easily-angered person or a sexually vigorous one.

An offensive formation with an unbalanced line and a snap directly to the running back rather than the quarterback.

Clipping of wildcat cartridge.

A wheel that can be adjusted so as to revolve either with or on the shaft of a capstan.

(no longer used) Clipping of wildcat money (“notes issued by a wildcat bank”).

To drill for oil in an area where no oil has been found before.