Learn Dutch: Het boek is stom. - The book is stupid.

In this sentence, stom comes after the verb is to describe the book. When an adjective is used like this (called a predicative adjective), it never gets an extra -e at the end. You only add an -e when the adjective comes directly before the noun, like in het stomme boek (the stupid book).

How can I say the book is 'too stupid' or 'very stupid'?

You can place a degree modifier right before the adjective. For example, use te for 'too' (Het boek is te stom), or heel or erg for 'very' (Het boek is heel stom).

Why is it Het boek instead of De boek?

Dutch has two words for 'the': de and het. Boek happens to be a neuter noun, so it always takes het. It is best to learn every new noun with its article so you know which one to use!

Does stom always mean 'stupid'?

While it literally means 'stupid' or 'dumb', Dutch speakers also frequently use stom to mean 'lame', 'annoying', or 'boring'. So if someone says Het boek is stom, they might just mean they did not enjoy reading it.