noun Psychiatry.
  1. inability to sustain one's attention or attentiveness, which is rapidly diverted from one topic to another: a symptom of a variety of mental disorders, as manic disorder, schizophrenia, or anxiety states.

Origin of distractibility

First recorded in 1900–05; distract + -ibility
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018