One example of a word that fits this category is: katamorphism. It means the metamorphism that takes place near the Earth's surface in which complex minerals break down into simpler ones.
overabundant
understating
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.
AbbaActaAghaAgmaAlbaAlfaAlgaAlmaAmiaAngaAnnaAnoaAnsaAntaAquaAreaAriaAseaAtmaAura
Anna
amaze
Alikeabovealone
malaria
determineddischargeddisengageddiminisheddiscoveredglisteningreconsiderstrangenessstupendousstolidnessstorminesssteadinesstriumphant
experience
natio
runners