unsociability

This term describes a personality trait characterized by a lack of desire or ability to engage in social interaction. It carries a more clinical or descriptive tone than "shyness," which implies fear or anxiety, or "antisocial," which in a psychiatric context can imply hostility or aggression toward society. It suggests a state of being withdrawn or aloof.

As an abstract noun representing a quality or state, this word is uncountable. It cannot be pluralized to describe multiple instances of the trait; instead, one must use partitive constructions such as "a streak of unsociability" or "levels of unsociability" to quantify the degree of the characteristic.