Thou... Vain Pox-marked Clack-dish
Parts of what makes up this insult can be found in "Richard II" spoken by "JOHN OF GAUNT":

This insult has been seen 3 times on this site. The first time was on Tuesday, April 3rd, 2018Enforce attention like deep harmony:
Where words are scarce, they are seldom spent in vain,
For they breathe truth that breathe their words in pain.

A total of 10308 insults have been uniquely generated 10778 times, with a total of 125000 (or 50 to the third power) insults available in the system!