Verb. Sap. and Verbum Sap mean "a
word to the wise (is sufficient)."
A search of Google yields two distinctly different modern usages of verb. Sap.: 1) warning to take heed, as in "That book is on the PATRIOT Act list. Verb. sap."; and 2) indication that no more detail needs to be explicitly stated, as in "You know the rest of the story. Verb. sap."
THE DICTIONARY OF PHRASE AND FABLE BY E. COBHAM BREWER
FROM THE NEW AND ENLARGED EDITION OF 1894
Verbum Sap [A word to the wise. ] A hint is sufficient to any wise man; a threat implying if the hint is not taken I will expose you. (Latin, Verbum sapienti.)
Merriam-Webster's Collegiate Dictionary
Etymology: short for New Latin verbum sapienti (sat est) a word to the wise (is sufficient)
enough said - used
to indicate that something left unsaid may or should be inferred
In 1665 Sir William Petty published a book entitled Verbum Sapienti, dealing with monetary theory. 1818 perhaps is the earliest year Webster found the modern usage, described here.