contradiction/falsehood
Contradiction/Falsehood: Setting every bit to 0; Outputting logically false to all possible logical inputs.
nonimplication/difference/but not
Nonimplicion/difference/but not means that the only true output is if p is true and q is false. Everything else is false. So if p is 0 and q is 1 the output should be 0.
Demonstration of the indicated keyword.
lab46:~$ P = 0 Q = 0 Output = 0 lab46:~$ P = 0 Q = 1 Output = 0 lab46:~$ P = 1 Q = 0 Output = 1 lab46:~$ P = 1 Q = 1 Output = 0 lab46:~$