1(Internet) a troll; someone who disturbs or sabotages online discussions by posting provocative or disruptive messages.
掲示板に荒らしが来てスレッドがめちゃくちゃになった。
A troll showed up on the forum and the thread got ruined.
荒らしの投稿は無視するのが一番だ。
Ignoring troll posts is the best approach.
モデレーターが荒らしを即座に削除した。
The moderator immediately deleted the troll's post.
2As a suffix/noun indicating making a mess of or vandalizing something — e.g. causing havoc in a place.
夜中に畑荒らしの被害が増えている。
There have been increasing incidents of people vandalizing fields at night.
公園荒らしをした犯人が捕まった。
The person who vandalized the park was caught.
3As a suffix meaning robbery or holdup — e.g. burglary of apartments (アパート荒らし).
深夜にアパート荒らしの被害が相次いだ。
There were repeated incidents of apartment burglaries late at night.
警察は近隣の荒らし事件を関連付けて捜査している。
The police are investigating nearby robbery incidents as related.
4A person who vandalizes or robs — a vandal or robber.
暴動で店を荒らした荒らしが数人逮捕された。
Several vandals who ransacked shops during the riot were arrested.
夜中に入って家を荒らした荒らしがいたと通報があった。
There was a report that someone had broken in at night and ransacked a house.