The most common and most likely answer to this crossword clue is the 7 letter word PARADOX
P
A
R
A
D
O
X
More clues leading to the result PARADOX
- A party vote below average is an apparent absurdity
- Republican party welcoming American leader in peace? That’s absurd!
- Spots a radical interrupting 3?
- Hit back with a note before ten? It can be true
- Soldier cuts short in broadcast? It doesn’t seem to make sense
- Neither up nor down, contrary Old Duke after a kiss? That’s an absurd proposition
- Contradiction of assistant with cool farmyard animal
- Word for which this isn't a clue?
- Bovine behind endless march— this makes no sense
- It seems odd, releasing end of rope from show bull
Buddy explains!

The straight part
We know that "that’s absurd" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case that’s absurd = paradox.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does PARADOX mean?
PARADOX noun- An apparently self-contradictory statement, which can only be true if it is false, and vice versa.
- A counterintuitive conclusion or outcome.
- A claim that two apparently contradictory ideas are true.
- A thing involving contradictory yet interrelated elements that exist simultaneously and persist over time.
- A person or thing having contradictory properties.
- An unanswerable question or difficult puzzle, particularly one which leads to a deeper truth.
- A statement which is difficult to believe, or which goes against general belief.
- The use of counterintuitive or contradictory statements (paradoxes) in speech or writing.
- A state in which one is logically compelled to contradict oneself.
- The practice of giving instructions that are opposed to the therapist's actual intent, with the intention that the client will disobey or be unable to obey.