Nouns ending with -heit and -keit in German

All German nouns that have the suffix -heit or -keit are feminine (i.e. have the article die), without exception (which is something we don’t see very often in German). To be fair, we should mention that there are a few extremely rare minerals whose names are seemingly exceptions to the rule because they contain the suffix -it after a root that ends in -he or -ke, e.g. der Luanheit (which is, in fact, Luanhe-it). In practice, you needn’t worry about these.

There is no difference in meaning between -heit and -keit (we will see later when to use which); -heit and -keit most commonly correspond to the English suffix -ness, as in:

or -ity:

but there are also many other possibilities:

Difference between -heit and -keit

It is almost always possible to tell whether to use -keit or -heit based on the suffix of the original adjective. If the adjective has one of the suffixes -ig, -lich, -sam, or -bar, the correct suffix is -keit:

-ig + -keit

-lich + -keit

-sam + -keit

-bar + -keit

Furthermore, adjectives with the suffixes -los and -haft take the suffix -igkeit, not just -keit:

-los + -igkeit

-haft + -igkeit

In virtually all other cases, the correct suffix is -heit. This is true, in particular, for all past participles used as adjectives:

past participle + -heit

With just a small number of exceptions, adjectives that don’t have one of the suffixes mentioned above combine with -heit:

almost anything else + -heit

Exceptions

Adjectives ending in -er are one source of exceptions; they usually take the suffix -keit. However, most of the resulting nouns are rarely used:

A few other roots ending in -er take the suffix -heit instead:

In a few cases, the ending -igkeit is used instead of -heit, often in the sense of “something like”. Note: The following list is incomplete; since the meaning often differs from the original adjective, it is better to assimilate these words naturally instead of memorizing them: