conceptual; ideational; notional
Refers to something existing as an idea or concept rather than as a concrete reality. Often used in philosophical or abstract discussions.
His explanation was conceptual and lacked concrete examples.
Describes something that is based on theory or abstract reasoning rather than practical application. Can carry a slightly negative nuance of being impractical or detached from reality.
その理論は観念的すぎて、現実の問題に使えない。
That theory is too theoretical to be applied to real-world problems.