How do you know if a word is masculine or feminine in german?

Answer 1

There is no way to tell by looking at a word. There are some rules but they do not cover all words.

Masculine nouns: Anything to do with weather, rivers, male occupations, nouns ending in -er, -lich, -ing, -ist.

Feminine Nouns: Any kind of ship, plane, or bike. Nouns ending in -ie, -ik, -heit, -keit, -taet, -ung, -schaft, foreign words.

Answer 2

In German, the gender of a noun is typically indicated by the article that precedes it (der for masculine, die for feminine, das for neuter). There are some patterns and rules to help determine the gender of a noun, but ultimately it's best to learn the gender along with the noun itself.