adjective (a)

• not clearly defined or easy to perceive or understand(adj.all)

  Example:
  Indistinct shapes in the gloom.
  An indistinct memory.
  Only indistinct notions of what to do.
  

  Antonym:
  distinct
  

  source: wordnet30
• Not distinct or distinguishable; not separate in such a manner as to be perceptible by itself; as, the indistinct parts of a substance.(adjective)

  source: webster1913