puzzling
adj.confusing and difficult to understand. You use this to describe something that feels like a mystery or a problem you cannot solve.
adj.causing confusion or perplexity due to being difficult to explain or understand. Often used to describe situations, behaviors, or evidence that lack a clear logical pattern.
“The detective found a puzzling clue at the scene.”
“The sudden change in the weather was puzzling to the scientists who had predicted a sunny day.”
“Despite years of intensive research, the disappearance of the ancient civilization remains a puzzling mystery that continues to divide the archaeological community.”
Typically used attributively before a noun or predicatively after linking verbs like 'be', 'seem', or 'find'.
“These events remain puzzling and require follow-up research.”
“That hidden heat could help explain several other puzzling features of Mars.”