I'd happily forfeit all my Christmas presents this year if internet people would all stop noising up discussions of consciousness with protests that it's ill-defined. One meaning is the opposite of unconscious. Another perfectly fine meaning is having subjective experience. Just like every other word with shades of meaning, we can tell from context - e.g. if the one using the word is a philosopher, or an anesthesiologist. Neither necessarily implies self-awareness. That's a third thing. Poorly understood, yes. Ill-defined - I just don't see it.