deep, profound
邃 centers on depth that is hard to reach or understand: physically deep spaces, or profound, far-reaching ideas.
邃 combines 辶 (movement) with 穴 (cave) and 㒸, a component that likely contributes the sound. The structure suggests going deep into a cave, hence profound or deep.
The movement radical 辶 leads into a cave 穴 with a complex lower part 㒸, like venturing far into a deep, dark cavern. That journey represents something deep and profound.
For スイ, imagine swimming deep into a profound underwater cave: swim -> スイ, and the deep water matches the kanji's meaning.