tweet author; poster of a tweet
Internet slang used on Twitter/X to refer to the person who posted a particular tweet, often in the context of a thread or reply.
This tweet author's other posts are also interesting.
I sent a reply directly to the person who posted the tweet.
Blend of ツイート (tweet) and 主 (ぬし, 'owner' or 'master'), formed as internet slang on Twitter/X.