Overview
A pocket veto is a legislative maneuver that allows a president or other official with veto power to exercise that power over a bill by taking no action ("keeping it in their pocket"), thus effectively killing the bill without affirmatively vetoing it. This depends on the laws of each country; the common alternative is that if the president takes no action a bill automatically becomes law.
Barbados
Similar to India [see India below], section 58 of the Constitution of Barbados, as amended by the Constitution Amendment Act 2021 (which transitioned the country from a Commonwealth realm to a parliamentary republic with its own head of state) states that the President shall declare his assent to a bill passed by Parliament or withhold his assent. However, much like in India, the Barbadian Constitution does not give a specific time frame for presidential action on a bill sent by the Parliament. Thus, by indefinitely postponing action on a bill, and not sending it back to Parliament, the president could effectively veto it.
Finland
The President of Finland has the power to pocket-veto bills passed by the parliament; however, such vetoes are temporary in effect.
India
Article 111 of the Indian constitution states that the President shall declare his assent to a bill passed by both houses of Parliament or withhold his assent, provided that may he return the bill to Parliament for reconsideration. If the President returns the bill, and Parliament passes it once again, with or without any amendments, the President cannot withhold his assent. However, the Indian Constitution does not give a specific time frame for presidential action on a bill sent by the Parliament. Thus, by indefinitely postponing action on a bill, and not sending it back to Parliament, the president effectively vetoes it. Zail Singh, the President of India from 1982 until 1987, exercised a pocket veto to prevent the Indian Post Office (Amendment) Bill from becoming law.
From Wikipedia (CC BY-SA 4.0).