The fundamental issue with saying "The largest number that can be described in 14 words or less plus one" is that it does not** define** a number, in the pure mathematical sense. In other words, it does not answer the question "What is the number?"

I would go with something such as :

"The factorial of Googolplex raised to the power of Googolplex, repeated ninety Googolplex times"

I leave it as an interesting mathematical exercise to show if this should preferably be defined as "the factorial of (Googolplex raised to the power of Googolplex, repeated ninety Googolplex times)", or "(The factorial of a Googolplex) raised to the power of Googolplex, repeated ninety Googolplex times". Either way, we are gazing in awe at a very large number.

We should not use constructs such as Graham's Number, as that requires a paragraph or more to define how it is constructed, and you cannot write down the number on a piece of paper to show anyone what it is.