Word formation - the basics

Word formation is the action of creating new words using existing ones in the language, by means of a number of techniques:

Compounding (Zusammensetzung)

By combining two or more self-standing words, the result is a new word, a compound. It is possible to combine different parts of speech together, as the examples show:
Noun + nounVerb + nounAdjective + verb
Garten-hausReit-hallehell-sehen

Derivation (Ableitung)

The creation of new words by adding suffixes and prefixes to existing words, and thus giving them new meanings, is called derivation.
Prefixes: be, emp, ent, er, ge, miss, un, ur, ver, zer ...
Suffixes: -bar, -haft, -ig, -isch, -lich, -los, -chen, -er, -heit, -keit, -ung ...

Conversion

A word can be used as another part of speech without any changes in form:
ernst(Adjective) -> Ernst(noun)
essen(Verb) -> Essen(noun)

Abbreviation (Kürzung)

New words can also be formed by shortening other words. Another example:
Base formsHof, Schuld
New words by compounding with different stems:Schulhof, Schuldfrage
New words by adding a prefixVorhof, Unschuld
New words by adding a suffixhöflich, schuldig
New words can't be formed by inflection

You can obtain different forms of a word by inflecting it at different grammatical categories, however this variation does not change the meaning of the word. You won't find them in a dictionary!