False! is the common way to denote the factorial of False.

The factorial of a number (or in this case, a random word) is the product of all the positive integers less than or equal to said number (or word or whatever). This can be shown by the following function where n is the integer (or random word) in question:

n! = n*(n-1)*(n-2)* ... * 2 * 1

So to calculate False! we would use the equation:

False! = False * (False-1) * (False-2) * ... * 2 * 1

If one does not want to calculate such a long equation, Stirling's Formula can be used to find the approximation for a factorial. Stirling's Formula states that:

n! ~ (n ⁿ) * (e ^-n) * (2 * pi * n) ^1/2 = (2 * pi) ^1/2 * (n ^n+1/2) * (e ^-n)

Taking the logaritm of both sides gives you (after some simplification):

ln n! ~ n ln n - n

So, for this case:

False! ~ (False ^False) * (e ^-False) * (2 * pi * False) ^1/2 and ln False! ~ False ln False - False