What is a "Twihard" exactly?

Well, for me

Twi-fan= you just like the books and movies, but are willing to accept that Harry Potter and other things are good as well. When twi-fans have a debate, they use good, structured debate, that makes sense.

Twi-hard= Pretty much in pag-ibig with Twilight. They occasionally use silly points such as 'Edward's hot', but can have decent reason from time to time.

Twi-tards. Completely obsessed with twilight, and fail to understand why anyone else might possibly like anything else. These people madami or less always use points such as 'EDWUURD ISSZSS FITTT' and they normally have VERY bad writing, almost like they've written it right and then purposely destroyed the sentence structure

I know you only asked for Twi-hards, but I find it easier to explain ipinapakita the whole scale :) x

Everyone seems to have their own definition of 'Twihard.' For some, it's the stereotypical tagahanga - the one with the shallow and ludicrous reasons for liking the series and who can't spell. Others just use it as an all encompassing term.

I use it when talking about the 'die hard' fans. The ones that are obsessed with the series - both books and movies.

I've seen people discuss it and their definition was a sexually driven offensive term.

I don't like explaining this, but I will.
A tagahanga who likes Twilight so much, it sexually arouses them.

I think it's inappropriate.

I always thought it was like hard core Twilight tagahanga or you know how they have those die-hard tagahanga medles, like that only Twi instead of die.

This is kinda' my short vocabulary on the Twilight liking stages.

Twifan: Semi to Dedicated
Twihard: Die-Hard
Twitard: Fanatic

Twihard=someone who likes Twilight.

Twilighter/Twilight tagahanga = The normal everyday Twilight tagahanga and they reason well. They are in every sense of the word, normal people
Twihard = A dedicated Twilight fan, may occasionally indulge in "Edward is hot" arguments, spells normally.
Twitard = The rabid Twilighter, stage one. Spelling is not up to standards but intelligible, indulges very often in "Edward is hot" fallacies.
Twazi = The rabid Twilighter, stage two. May committ murder on behalf of Stephenie Meyer, spelling is unintelligible. Behaves like the most extreme of extreme internet trolls.