Limiting or controlling the freedom or actions of someone or something.
The new policy is quite restrictive, preventing employees from working remotely.
Imposing limitations or constraints on what is possible or allowed.
The restrictive rules of the club made it difficult for new members to join.
(Grammar) Of a relative clause or modifier: identifying and essential to the meaning of the noun it modifies, and therefore not set off by commas; limiting.
In the sentence "Students who study hard succeed," the clause "who study hard" is restrictive.