[Latin, For this; for this special purpose.] An attorney ad hoc or a guardian or curator ad hoc is one appointed for a special purpose, generally to represent the client, ward, or child in the particular action in which the appointment is made.
An administrative agency, a legislature, or other governmental bodies may establish ad hoc committees to study particular problems. For example, a city government may establish an ad hoc committee to investigate and discuss the placement of a new stadium in the city. Likewise, an administrative agency in some jurisdictions may engage in ad hoc rulemaking, whereby the agency establishes specific procedures to promulgate a rule without necessarily adhering to formal rulemaking requirements.