What does the term "subtle" commonly mean?

The term "subtle" commonly refers to something that is hardly noticeable or that requires careful observation or thought to perceive. This meaning suggests that a subtle distinction or difference can be so slight that it easily escapes casual observation. In various contexts, subtlety can imply delicacy or finesse, often relating to things that are nuanced or not overtly apparent.

For example, in art or communication, a subtle message might convey a deeper meaning that is not immediately obvious, requiring the audience to engage thoughtfully. This nuanced understanding aligns with the definition provided in the selected answer.