This is the 11480th most frequent Russian word.
долгосрочным
"Долгосрочным" means "long-term."
Here, "долгосрочное" is used as an adjective describing the type of impact that spans over a long duration.
Эта стратегия окажет долгосрочное влияние на экономику.
This strategy will have a long-term impact on the economy.
In this sentence, "долгосрочный" modifies "контракт" to denote that the contract is intended to last for an extended period.
Он заключил долгосрочный контракт с компанией.
He signed a long-term contract with the company.
Here, "долгосрочные" is a plural adjective describing "проекты," indicating that the projects span a long time frame.