What are Guinan's powers from Star Trek: TNG?

Question

In Star Trek: The Next Generation episode "Q Who," season 2, episode 16, Q seems disturbed by the presence of Guinan to the point of raising his hands as if to use his powers on her. Guinan responds by raising her hands as if to cast a "magic" spell of her own.

Is it ever established what powers she or her race may possess?

Answer 1

Guinan, perhaps her whole species, is able to understand the 'correct' state of the universe. Take for example in Yesterday's Enterprise she knows details about the 'other' universe. The universe as it was during the rest of the series with the Enterprise as a ship of peace, not a ship of war.

This is, essentially, the counter power to Q's ability to alter the universe at will. It suggests that the power the Q hold is transparent to Guinan. She can see through their alterations to the mechanics of those actions and the state of the universe before those actions. Possibly, she can counter their magical technology, although that's just conjecture.

Just being able to understand the 'true' state of things would be enough to limit Q's power, which would be frightening to him. And what the Q do to the universe would be equally as upsetting to Guinan.

Answer 2

When Guinan was ripped from the Nexus in "Generations", part of her was still left there. She told Picard she couldn't go back with him because she was already there. The part of her left in the Nexus, a place where time had no meaning, gave her her sixth sense. This explanation was in the original Generations script but was later edited.

Answer 3

I have always wondered about this myself. I would say that while her species does have incredible mental abilities, they would not be anywhere near a match for a Q. The Borg ran roughshod over her people. We know the Borg are not at the level of the Q. Here are some theories:

1. Guinan was at the point where she she was going to possibly attack him with her mind, regardless of her ability to damage him. We have seen Worf ready to attack Q despite his inability, and we have seen Sisko actually punch Q. So she may have been "blowing smoke" or angry enough to attack with out causing damage.

2. I am much more intrigued by this possibility: What if she possesed a Q weapon, unseen by the crew but deadly to Q? We know Janeway and Tuvock had Q weapons and at one point were an extreme danger to the Q. Janeway's weapon was represented by a flintrock rifle; Guinan's may have been represented with a magic spell. Q did back off. Why would she have it? Any number of Qs could have given it to her at any time over the course of her long life. Why? There are many reasons possible. Law enforcement of renegades or she like Janeway participated in a Q war, or it was given to her by another, friendlier, Q to protect her from this Q or others.

3. One last theory, and I imagine this one is a little unlikely. She may have been a Douwd or an Organian masquerading as an Al-Aurian. We know both these highly advanced species, as well as the Q themselves, will do this from time to time and, if governed by a non-interference directive, would not use her abilities to help or hurt the aliens she is currently with. But she might use her abilities in self-defence against Q. He would of course see through her facade.