In the English language there only appears to be one twelve-letter word that ends in ok.
That word is gobbledygook, which is defined as incomprehensible jargon.
intoxication
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.
r 12
Lighthearted is a 12 letter word. Lithographed is another 12 letter word that starts with L and ends with D.
manufactured
manufactured
intellectualmotorcyclistsatisfactionwatercoolersarticulatingcitizenshipsintercompany
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overabundant
recalcitrant
constituents