Milk-and-water and Unoccupied

Milk-and-water adjective - Lacking in qualities that make for spirit and character.

Unoccupied and milk-and-water are semantically related. In some cases you can use "Unoccupied" instead an adjective phrase "Milk-and-water".

Unoccupied adjective - Not held or filled or in use.

Milk-and-water and unoccupied are semantically related. Sometimes you can replace phrase "Milk-and-water" with "Unoccupied", this terms are similar.