Learn Swedish: Det är en bra egenskap.

Nouns ending in -skap can be either en or ett words. A helpful rule of thumb is that abstract qualities, sciences, and skills are usually en words (like en egenskap for a quality, or en vetenskap for science). On the other hand, words describing a state, a condition, or a group of people are often ett words (like ett sällskap for company, or ett äktenskap for marriage).

How does the suffix "-skap" change the meaning of the root word here?

It combines the adjective egen, meaning "own" or "characteristic of", with the suffix -skap, which works like the English "-ship" or "-ness". So, en egenskap literally translates to something like "own-ness", which creates the noun for a specific trait, characteristic, or quality that belongs to a person or thing.

Since "egenskap" is an en-word, why does the sentence start with "Det är" instead of "Den är"?

When introducing or identifying what something is using the structure "It is a..." or "This is a...", Swedish always uses the neuter pronoun det as an impersonal starting point. This rule applies regardless of the noun's actual gender. Once the noun has been introduced, you would then switch to using den in the following sentences to refer back to it.

Why doesn't the adjective "bra" take an ending to match the en-word noun?