Mildly means slightly or to a small degree. When something affects you mildly, it has a gentle, modest effect rather than a strong one. If you're mildly annoyed by your little brother's singing, you're a bit bothered but not truly angry. If the weather forecast predicts mildly warm temperatures, expect pleasant warmth, not scorching heat.

The word suggests something barely noticeable or just enough to register. A teacher might be mildly disappointed if you forgot your homework once (a little let down, but understanding), versus deeply upset if you never turned in assignments. Food described as mildly spicy won't make your mouth burn; it has just a hint of heat that most people can handle comfortably.

People often use mildly to soften their statements. Saying “I'm mildly concerned about the storm” sounds calmer than “I'm worried about the storm,” even if you mean nearly the same thing.