an·ti
/ˈan(t)ē,ˈanˌtī/
preposition
opposed to; against.
"I'm anti the abuse of drink and the hassle that it causes"
adjective
opposed.
"neither side in the debate, whether anti or pro, has offered a particularly convincing case"
noun
a person opposed to a particular policy, activity, or idea.
"a shadow army of antis who endanger your sport"