Opponent and Vilifier

Opponent noun - One that takes a position opposite another in a competition or conflict.

Vilifier and opponent are semantically related In some cases you can use "Vilifier" instead a noun "Opponent".

Vilifier noun - One who attacks the reputation of another by slander or libel.

Opponent and vilifier are semantically related in someone hated or competed against topic. Sometimes you can use "Opponent" instead a noun "Vilifier".