I'd always thought that Araucaria's grid of undefined 7-letter Shakespearean characters (who knew there were so many of them?) was the hardest Genius puzzle by far. Not no more.
Themed clue , so no defn and an extra letter in the wordplay:
12a Very drunk, hearty drinker is one farthing short (6) the answer is quaver but how does it parse please ..and extra letter? R? F?