noun (n)

• state of elementary or undifferentiated consciousness(noun.cognition)

  Synonym:
  awareness
  

  source: wordnet30
• the faculty through which the external world is apprehended(noun.cognition)

  Synonym:
  sensation, sense, sensory faculty, sentiency
  

  source: wordnet30
• the readiness to perceive sensations; elementary or undifferentiated consciousness(noun.attribute)

  Example:
  Gave sentience to slugs and newts.
  

  Antonym:
  insentience
  

  source: wordnet30
• The quality or state of being sentient; esp., the quality or state of having sensation.(noun)

  source: webster1913