Input and output clamping current of the IC 4082
Referring to a data sheet for the HEF4082B, we have: 



This means that you must ensure that the current into any input never exceeds +/-10mA under any conditions or the chip may be immediately damaged. It does not mean that you can apply 9.9mA and expect long life, nor can it be expected necessarily that the chip will operate properly. 

As the "Conditions" implies, this (relatively high current flowing into or out of the input) will only occur if you apply a voltage greater than Vdd or less than Vss. 

Similarly, the output clamping current has the same limit: 



So if you pull the output beyond the rails, you must never exceed 10mA current.