To be honest, I think the Q are the masters of Bravado. It seems to be, that the franchise lightly hints at this too.
1. We know a Q dies, on Earth, due to a tornado. [I hope im recalling correctly, havent seen that episode for a while]
2. Q is shown to be 'stripped of his powers'.
3. There is a civil war in which Q die.
4. Q seems intimidated by Guinan, and she seems poised to defend herself. A ridiculous notion if it were a true 'god' however she seems serious enough. He even calls her an 'imp'....which implies some sort of impish behaviour against the continuum.
I have always suspected the Q exaggerate their power to portray an aura of invincibility to the less developed races [who have insufficient resources to prove otherwise]. No doubt they are vastly powerful....but not omnipotent. The mere word makes no sense.
This is easily explained with the simplest math: Two Q can simply over-power a single Q.
1. A tornado killed humans that were once Q.
2. Q can be stripped of his powers by multiple Q, and could possibly have elected to grant this ability to a governing party in the continuum, until chaos broke out during the civil war, at which point they could have simply elected multiple Q to defy the will of any party that attempts to enforce rule.
3. The Q civil war was the second time Q provided a visual 'representation' of the continuum: "I'm simply allowing you to perceive it in the context your human mind can comprehend." It is actually suggested that the crew wouldn't comprehend the continuum, so the viewers wouldn't either. During the episode, Q were shown injured, one was shown with no legs, but none were shown dead. It's up to the viewers to interpret and give meaning to what an injured Q represents, since they're not human, their weapons weren't really shooting 'bullets' so we shouldn't assume they they actually suffering from flesh wounds.
4. Guinan is the most interesting argument for skeptics of Q's power but it says more that she would effort to defend herself with attack or block his power in some manner. It doesn't, however - present the intensity of the attack Q planned to use, and we cant assume he was willing to blink her completely out of existence.
"The mere word makes no sense." - in a way, I agree. But it's close enough to the definition of Q, which at some point, we just have to accept there are no limits without it having to be demonstrated. Quinn made Voyager sub-atomic in size.. a mere quantum-scale speck of matter and energy, yet with all the crew still alive and functioning, along with all the ship systems. That, and or positioning Voyager in a realm of 'nothingness' before space expanded with the big bang? Basically, that's when you stop questioning Q's abilities. I mean - it seems if he can imagine it, his will can be done.