I have not looked at the claims for static on the Microchip data sheet,
     but I suspect that "static-hard" may be a reference to how much
     static (i.e. voltage level, current and time) the device can
     withstand without destroying either the input buffers, output buffers
     or the control buffers.  I could be wrong as I have not looked at the
     context in which Microchip uses this phrase.

     The bypass cap suggested by others, is a good idea as it gives the
     high voltage static (could be 1,000 volts or more) a place to discharge.
     Since the current is usually extremely low, a lot less than a microamp,
     a small cap should work just fine.

     Typically the inputs of CMOS buffers are designed to withstand around
     1,000 to 2,000 volts for a couple of picoseconds at very low current
     without damaging the device.  The design, by-the-way, is non-trivial
     and many semiconductor manufactures have difficulty meeting the IEC
     specification for static electricity.

     Good luck!