schizoid

adj

1. Characterized by social withdrawal and emotional coldness or flattened affectivity.

   “Abstract symbol systems, such as mathematics, are especially valuable for object-seeking for schizoid personalities. By means of such symbolizations, object contact may be sought and obtained, while at the same time a psychological distance may be maintained between self and other; it is virtually impossible to have a personal relationship and at the same time to maintain such distance.”

2. (archaic)Schizophrenic.
3. (figuratively, offensive, sometimes)Behaving as if one has more than one personality; wildly changeable or unpredictable.

   “Babits himself never fully lived up to this program; indeed, the declaration itself shows his schizoid attitude toward poetry: he wants to say out loud that he does not want to be heard.”

   “I continued to live a schizoid existence—working as a schoolteacher, molding myself into what I imagined was a traditional male image […] — but I couldn't fool myself. I was a queer in lumberjack drag.”

noun

1. Someone with schizoid personality disorder.
2. (archaic)Someone with schizophrenia.