Black lips or having very dark colored lips is contributed by several factors and can be used as indicators for certain conditions that are happening inside the body. Though very rare, there are certain severe medical conditions that can cause the lips to turn a darker shade or even black like having cancer. It can be contributed by living a modern lifestyle, certain eating habits, and some medications. There are patients that naturally have black lips or dark-colored lips.
Substantial - either now or in the next three months. 1  significant harm or danger due to your physical or mental health or behaviour.  being unable to carry out many personal care and daily household chores, causing significant risks to your independence.
Something substantial is large in size, number, or amount: If you want to say someone spent a lot of money without being too specific, you could say they spent a substantial amount of money. The adjective substantial derives from the Latin substantia substance, which means stuff. A substantial meal is large enough to satisfy hunger. A substantial structure is strongly made or built. And a substantial man possesses wealth and property. Related to this last sense, a man of substance refers to a wealthy man with property.