Generally stands for 'What the fuck'. Most people use a question mark afterwards to get the point through. Rather than using the same term for the other 'w's, who, when, where, and why, it makes more sense to actually state the word and follow it with 'tf'

Capitalization doesn't really matter.
This term can also be likened to 'What the shit?' which is more comical and has a tantamount meaning.

A few weeks ago, no one had “cheugy” in their vocabulary . Now everything is saturated with the word. It’s in our heads. It’s in our homes. Everyone is asking: “Am I cheugy? Am I a basic ass bitch? Am I GUILTY of being cheugy?”

The proliferation of cheugy in the mainstream discourse can only be attributed to one source: mental terror. It’s an orchestrated psychological trap to make you question your tastes and interests in the eyes of others.

You are not a cheug. YOU’RE PERFECT!!!!

It is very suspicious that the cheugy mascot is a Minion, a literal cyclops, a deformed
yellow panopticon in overalls ... do not let the all-seeing eye to control you. Be vigilant. Resist cheugy psyops.

The World Taekwondo Federation.
WTF, holds many competitions throughout the world.

Denotes: What the Fuck!

1. What the fuck.
2. World Tae Kwon Do Federation

Of course there is only one known definition of the phrase Wtf and that, of course is Wilbur, that frigg-nugget.

Stands for What The Fuck.