Synonyms for Prevent:

n.

knock something on the head, avoid, get in the way of something, squash. preclude (noun)
keep from happening, stop from, halt, intercept, circumvent, hold off, arrest, countercheck, debar, turn aside, override, limit, obviate, draw off, ward off, repress, fend off, stave off, nip in the bud, put a stop to.
prevent (noun)
foreclose, keep, forbid, forestall, preclude.

v.

dissuade (verb)
divert, restrain, dampen, deflect, avert, daunt, admonish, ban, bar, dissuade, deter, depress, derail, check, disincline, discourage, chill, dishearten, inhibit, intimidate.
keep from happening or continuing (verb)
debar, hold off, Forfend, chill, nip in the bud, restrict, avoid, hinder, halt, prohibit, block, limit, ward off, repress, inhibit, turn aside, avert, forbid, bar, stave off, preclude, intercept, forestall, check, put a stop to, obviate, arrest, restrain.
prohibit (verb)
preclude, disapprove, disallow, control, prohibit, restrict, outlaw, refuse, suppress, disqualify, deny, block, oppress, constrain, forbid, reject, curb, curtail.
retain (verb)
hold, conserve, preserve, retain, reserve, maintain, hinder.
social (verb)
keep.

Other synonyms:

stave off, Forfend. avoid, keep from. silence. hold off. disturb, squash. counteract
countercheck.
cut off
intercept.
defend
retain.
exclude
foreclose.
make unnecessary
obviate.
prohibit
debar, prohibit, bar.
resist
keep from.

Usage examples for prevent

  1. If I could do so it would prevent your position being turned. – With Moore At Corunna by G. A. Henty
  2. Nothing can prevent me. – Master Olof A Drama in Five Acts by August Strindberg
  3. The Countess would certainly find means to prevent her son's intended journey. – Fickle Fortune by Elisabeth Burstenbinder (AKA E. Werner)