definition of
prevent

[1] #1 prevent v. [forestall, foreclose, preclude, forbid] keep from happening or arising; make impossible; "My sense of tact forbids an honest answer"; "Your role in the projects precludes your involvement in the competitive project". wn

[2] #2 prevent v. [keep] stop (someone or something) from doing something or being in a certain state; "We must prevent the cancer from spreading"; "His snoring kept me from falling asleep"; "Keep the child from eating the marbles". wn