mean business

and I don't mean maybe

Indicating that one is serious and not joking about a matter.

bad business

Synonym of bad news (“irritating, troublesome or harmful thing, situation or person”).

business as usual

The normal course of an activity, particularly in circumstances that are out of the ordinary.

business end

The part of an object (chiefly a tool or weapon) that is physically used for its operation, rather than some other part such as the part by which it is held.

business girl

A female prostitute.

do one's business

Especially of a house pet: to defecate or urinate.

get down to business

To commit oneself to a task or activity that is employment-related or that requires serious effort or concentration.

give someone the business

To treat someone harshly or in a wrongful manner, such as by abusing, deceiving, or manipulating.