Subtly means doing something in a delicate, understated way that's not immediately obvious. When you act subtly, you're being gentle and indirect rather than loud and obvious.

If your friend seems sad and you subtly try to cheer them up, you might crack a small joke or suggest their favorite activity without making a big announcement about what you're doing. A subtle hint is one that requires attention to notice: a teacher might subtly clear her throat to signal that the class is getting too noisy, rather than shouting for quiet.

Artists use subtle colors when they want soft, barely-there changes between shades. A musician might subtly speed up the tempo so gradually that listeners feel the energy building without quite realizing what's happening. When someone subtly changes the subject during dinner, they guide the conversation in a new direction so smoothly that no one notices the shift.

The opposite of subtly is obviously or blatantly. Subtlety takes skill and attention: you have to understand your situation well enough to make small, careful adjustments instead of big, dramatic ones. Sometimes the most effective way to accomplish something is to do it so subtly that it seems to happen naturally.