Fluff can have different meanings depending on the context. Here are some definitions from various sources:

• A soft, light, downy mass
• To shake or puff out (feathers, hair, etc.) into a fluffy mass
• Something inconsequential or pointless
• Unnecessary bullshit
• Entertainment that lacks substance

Examples of fluff include a fluff of summer clouds, the fur of a small animal, and an article that talks about movie stars and gossip. Fluff can also refer to actions such as shaking a pillow to make it appear larger or forgetting ones lines in a play.