Chilly describes something that's uncomfortably cold, but not freezing. A chilly morning makes you wish you'd grabbed a jacket before heading outside. Chilly weather sits somewhere between cool and cold: warm enough that you won't get frostbite, but cold enough that you shiver and your breath makes little clouds in the air.

When fall arrives and temperatures drop, people start describing days as chilly. A swimming pool might feel chilly in early June before the water has warmed up. Even a room can feel chilly if someone left a window open overnight.

The word also describes a person's unfriendly behavior. When someone gives you a chilly reception, they act cold and distant rather than warm and welcoming. If your friend seems chilly toward you after an argument, they're being standoffish and cool in their attitude. This emotional meaning comes from comparing an unfriendly person to cold weather: both make you want to find somewhere warmer.

Notice that chilly is milder than freezing or frigid. A chilly day might make you grab a sweater, while a freezing day might require a heavy winter coat, hat, and gloves.