noun
anon; anonymous poster
Internet slang from 2channel (2ch), referring to the default name given to users who post without a handle. Often used humorously or to refer to an anonymous person in online contexts.
名無しさんがまた面白いコメントを書いてたよ。
An anon wrote another funny comment.
このスレには名無しさんばかりだね。
This thread is full of anons, isn't it?