Is "vindicate" a form of "indicate"

The online dictionary has the following to say:

Indicate >> to point out, show...

Vindicate >> to clear from censure or doubt by means of demonstration...

"Showing" is a means of "demonstrating" so is it reasonable to believe that "vindicate" is a form of "indicate?"

The word "re-enter" is derived from the preposition "re" and the root word "enter." What preposition (if any) would be represented by the "v" in "vindicate"? If there is none, how would the "v" cause "vindicate" to be a form of "indicate."

They are related in that they both came from the Latin word dicere, meaning "to say". Etymonline shows that vindication comes from vim + dicere, whose roots mean something like "to say with force". And indication comes from in + dicere, whose roots mean something like "to say upon". So the prefix for vindication is vim, not v- (and it technically is a word and not a prefix; vindication is a compound word, and not prefix + word).