›to balance one effect against an opposing effect, so that there is no great difference as a result: The price of petrol products was offset by a decline in motor vehicle prices.offset sth against sthOffset any losses against your overall income.
›ENVIRONMENT, SOCIAL RESPONSIBILITYto pay an amount of money when you do something, for example travelling by air, that produces a lot of harmful waste products. The money is used to do something that protects against climate change, such as planting trees: When we are forced to travel by air, we always check the box to choose to offset our flights.