notionally

not-comparable

In a notional, imaginary or speculative sense; in theory.

Japanese Meaning

理論上 / 概念上 / 仮定上 / 想定上

The proposal is notionally attractive, but its implementation would be prohibitively expensive.

その提案は概念的には魅力的だが、実行するには非常に高額になるだろう。

Sense（1）

In a notional, imaginary or speculative sense; in theory.