Subaqueous and Underground

Subaqueous adjective - Growing or remaining under water.

Underground and subaqueous are semantically related. in usually down topic. In some cases you can use "Underground" instead an adjective "Subaqueous".

Underground adjective - Undertaken or done so as to escape being observed or known by others.

Subaqueous and underground are semantically related. Sometimes you can use "Subaqueous" instead an adjective "Underground".