Quick answer
A mismatch in both directions. Fine words sit oddly on a fool, and lies sit far worse on a ruler.
Read both lines
The proverb argues from the lesser to the greater. If eloquence is incongruous coming from a fool, the way a gold ring is incongruous in a pig's snout at 11:22, then falsehood from someone with power is worse by an order of magnitude. What raises the stakes in the second line is authority: a prince's word moves things, so a lying prince is not merely unbecoming but dangerous. The verse quietly assumes that speech should match the speaker, and that the gap between the two is always noticeable.
Related: Proverbs 11:22 · Proverbs 16:12–13 · Proverbs 29:12
New King James Version®, Copyright © 1982, Thomas Nelson. All rights reserved. Full copyright information. Scripture provided by API.Bible.
Go Deeper
If this verse has been used to put weight on you that it was never carrying, ask about it directly.