illogical
adj.not making sense or not following clear thinking. You use this to describe an idea or action that does not have a good reason behind it.
adj.lacking sense or sound reasoning; contrary to the principles of logic. Often used to describe arguments, decisions, or behaviors that fail to follow a rational sequence.
“It is illogical to buy a car if you cannot drive.”
“The manager's decision to cut the marketing budget during a sales slump seemed completely illogical to the team.”
“While the protagonist's actions may appear illogical at first glance, they are driven by a deep-seated emotional trauma that bypasses rational thought processes.”
Often used predicatively after linking verbs like 'seem', 'sound', or 'be'.
The correct prefix for 'logical' is 'il-', not 'un-'.
“I feel slightly envious too, which is illogical.”
From il- + logical.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.