Both 貪 (どん) and 欲 (よく) are standard on'yomi. 貪 means to covet, and 欲 means desire. たんよく is a common misreading of 貪. It denotes excessive or insatiable desire for something, especially wealth or power; greed or avarice. It implies a strong, often negative, urge to acquire.

貪 (どん) も 欲 (よく) も標準的な音読み。貪（たん）と読み間違えやすいので注意。限りなく欲しがること、強欲な様子を表します。