Subnormal (adjective)

1. Being below the normal or typical standard in some aspect, such as intelligence, development, or function.
2. Less than average or expected in quality, quantity, or level.

Origin:

From sub- 'below, less than' + normal, from latin norma 'a rule, pattern, standard'. the word dates back to the late 19th century.

Examples:

1. She was diagnosed with a subnormal IQ.
2. The company was accused of providing subnormal working conditions.
3. The new software was performing subnormally due to a bug.
4. The subnormal temperature was causing concern among the scientists.
5. The subnormal rainfall has resulted in a severe water shortage.