Trick or Treat is 12 letters but it's 3 words.
Successfully is a 12 letter word with three set of double letters. Stubbornness is another 12 letter word.
bibliography
gobbledygook
a 12 letter word adjective that ends with ry that's expresses an emotion
underwhelmed
outrageously
appellations, appeasements
seismography
Bloodcurdling
Trick or Treat is 12 letters but it's 3 words.
Successfully is a 12 letter word with three set of double letters. Stubbornness is another 12 letter word.
Brown recluse is a 12-letter word for a type of spider.
Lighthearted is a 12 letter word. Lithographed is another 12 letter word that starts with L and ends with D.
manufactured
manufactured
three is a fourth of 12