cool cat

Noun

 * 1)  A person who performs or appreciates jazz, especially one whose style of speech and movement is relaxed and rhythmic.
 * 2)  A person who is at ease and self-assured; one who is calm and composed in interactions with others.
 * 1)  A person who is at ease and self-assured; one who is calm and composed in interactions with others.
 * 1)  A person who is at ease and self-assured; one who is calm and composed in interactions with others.

Usage notes

 * Sometimes used in the expanded form one cool cat.