Abysmal (adjective)

1. Extremely bad, poor, or inferior.
2. Incredibly deep or profound.

Origin:

Mid 17th century: from abyss + -al.

Examples:

1. The performance of the team was abysmal.
2. The customer service was abysmal.
3. The test scores were abysmal.
4. The book had an abysmal plot.
5. The abysmal depth of the ocean is hard to imagine.