1. superlative form of chill; most relaxed, calm, or laid-back
Usage: informal; slang
2. superlative form of chill; coldest in temperature
Usage: less common in modern usage

Examples

• He's the chillest person I know—nothing ever stresses him out.
• That's the chillest vibe at any coffee shop in town.
• She has the chillest attitude about deadlines.
• The chillest part of the day is early morning.
• My friends think I'm the chillest because I never get angry.