Absurdle is an adversarial variant of the charming and (currently) viral word guessing game Wordle.
The mechanics of Absurdle are identical to Wordle, or as close as I can make them. Among other things, they use very similar word lists. (There are actually two word lists in Wordle: one is a list of 2,315 words which can appear as answers, and the other is a list of 10,657 rather more obscure words which are allowed as guesses but will never appear as answers.) The major difference is behind the scenes.
Wordle picks a single secret word at the beginning of the game, and then you have to guess it. Absurdle gives the impression of picking a single secret word, but instead what it actually does is consider the entire list of all possible secret words which conform to your guesses so far. Each time you guess, Absurdle prunes its internal list as little as possible, attempting to intentionally prolong the game as much as possible.
The easiest way to explain this is with a worked example. Suppose your first guess is "TERNS".
Absurdle considers every word in its list of 2,315 possible secret words and figures out what its response would be in each case.