Supply as per GST Law :
Section 7
(1) For the purposes of this Act, the expression “supply” includes–– All forms of supply of goods or services or both such as sale, transfer, barter, exchange, license, rental, lease or disposal made or agreed to be made for a consideration by a person in the course or furtherance of business;
i. Import of services for a consideration whether or not in the course or furtherance of business;
ii. The activities specified in Schedule I, made or agreed to be made without a consideration; and
iii. The activities to be treated as supply of goods or supply of services as referred to in Schedule II.
(2) Notwithstanding anything contained in sub-section (1),––
(a) Activities or transactions specified in Schedule III; or
(b) Such activities or transactions undertaken by the Central Government, a State Government or any local authority in which they are engaged as public authorities, as may be notified by the Government on the recommendations of the Council, shall be treated neither as a supply of goods nor a supply of services.
(3) Subject to the provisions of sub-sections (1) and (2), the Government may, on the recommendations of the Council, specify, by notification, the transactions that are to be treated as—
(a) A supply of goods and not as a supply of services; or
(b) A supply of services and not as a supply of goods.
Main part of definition in section 7(1)(a) of CGST Act makes it clear that all supplies made for consideration in course of business are subject to GST.
The term ‘supply’ is from the point of view of person who is supplying and not person who is receiving the supply. Thus, if supplier is not in the business of supplying the goods or services, GST is not applicable (and consequently, the recipient will not be liable to pay tax under reverse charge).