As per Lawkidunya Taxable Activity is an activity carried out continuously or regularly by a business, trade, manufacturer, professional, association or club.

Taxable Activity in Sales Tax Act

taxable activity, means any economic activity carried on by a person whether or not for profit, and includes:-
(a) an activity carried on in the form of a business, trade or manufacture;
(b) an activity that involves the supply of goods, the rendering or providing of services, or both to another person;
(c) a one-off adventure or concern in the nature of a trade; and
(d) anything done or undertaken during the commencement or termination of the economic activity,
but does not include –
(a) the activities of an employee providing services in that capacity to an employer;
(b) an activity carried on by an individual as a private recreational pursuit or hobby; and
(c) an activity carried on by a person other than an individual which, if carried on by an individual, would fall within sub-clause (b).