Is this capacitor from a ceiling fan dangerous?
The capacitor is not dangerous when the fan is unplugged and has been off for a while.  The type of motor in the fan uses the AC frequency to run, and when everything is balanced has zero torque at zero speed.  The capacitor unbalances the winding so that there is torque at low speed.  It is usually switched out once the motor gets going, since it decreases efficiency if left in the circuit during normal operation.

If the cap is switched out of the circuit at just the right time, it could be left with high voltage on it.  Depending on the cap type, it could retain that voltage for quite a while.  Leakage should have discharged it over several days, but I'd probably quickly short with with a screw driver or a wire before touching it anyway.

WVAC stands for "working volts AC".