sensitiveness

noun

1. The capacity for or an act of responding to a stimulus: feeling, sensation, sense, sensibility, sensitivity, sentiment. See awareness/unawareness.
2. The quality or condition of being emotionally and intuitively sensitive: feeling, sensibility, sensitivity. See awareness/unawareness.

The noun has 3 meanings:

Meaning #1: sensitivity to emotional feelings (of self and others)
  Synonym: sensitivity

Meaning #2: (physiology) responsiveness to external stimuli
  Synonyms: sensitivity, sensibility

Meaning #3: the ability to respond to affective changes in your interpersonal environment
  Synonym: sensitivity
  Antonym: insensitiveness (meaning #1)