Questions & Answers about Wat de leugenaar zegt, is een leugen.
Why is wat used here instead of dat?
In this sentence, wat is a free relative pronoun. It doesn't refer back to a specific noun earlier in the sentence (which is when you would use dat or die). Instead, it acts as an independent concept meaning "that which" or "whatever", and the entire clause Wat de leugenaar zegt functions as the subject of the main verb is.
Why does the second half of the sentence start with the verb is?
This is the standard Dutch V2 (verb-second) rule in action. The entire free relative clause Wat de leugenaar zegt occupies the first grammatical position of the main sentence. Because the main verb must come second, is immediately follows the comma.
The translation says "Whatever". Can wat mean "whatever" on its own?
Yes. In a free relative clause, wat literally means "what" or "that which", but it often translates naturally to "whatever" in English when stating a general truth. If a Dutch speaker wanted to put extra emphasis on the "ever" part, they might add ook inside the clause: Wat de leugenaar ook zegt, is een leugen.
Why is the verb zegt placed at the end of the first clause?
The clause Wat de leugenaar zegt is a subordinate clause introduced by the relative pronoun wat. In Dutch subordinate clauses, the conjugated verb is pushed to the end of that clause, right before the comma.