the sound one makes when expressing displeasure, dissatisfaction, annoyance, not having anything to say, being bored, being sarcastic, that something is incredibly obvious; kind of like a sigh, (only you can have full conversations with it); goes in conjuction with rolling your eyes or raising an eyebrow.
Miguel: go do the dishes
Miguel: what, you don't want to?
Amanda: not really.
Miguel: eckh. Then I'll do them myself.