A troll is someone who posts something purely to be antagonistic or to be malicious.

For example, Turnoi arguing and disputing every single thing I post, regardless of the validity of the content, is him being a troll. Posting fictional or fallacious posts about me, my gender, identity and qualifications is him being a troll. Creating fake profiles in order to discredit me is him being a troll.

His posts denigrating reputable institutions such as CESOL, TBC, English Literature degrees and the DELTA qualifications, simply to take potshots against something I've endorsed, is him being a troll.

At least I hope that's him trolling... I'd hate to think anyone teaching really was that ignorant of international ESL institutions!