尽くす expresses the idea of doing something completely, leaving nothing undone. When attached to a verb stem, it gives a nuance of doing that action until there is nothing left, like using up all your energy or resources. It is often used with effort, money, or time. For example, 使い尽くす means to spend all your money, and やり尽くす means to do everything possible. It carries a sense of finality and thoroughness.

With nouns, it commonly appears in fixed expressions like 全力を尽くす (to do one's best) or 義務を尽くす (to fulfill one's duty). In these cases, it means to devote or dedicate oneself completely to that thing. This usage is more formal and is often found in speeches, written statements, or serious contexts. It is not used in casual everyday conversation about trivial matters.