Knigge
People:

Adolph Franz Friedrich Ludwig (Freiherr von) Knigge (1752–1796), a German writer
Rolf Peter Knigge (1951–1990), a German pop singer/songwriterEtiquette

Adolph Freiherr Knigge's 1788 book On Human Relations is still often referred to as Knigge
Derived from the above, any ruleset or book that concerns itself with etiquette

See also
32899 Knigge (1994 PY1), a main-belt asteroid discovered on 1994 by F. Borngen