also: ノンビリや
noun
easygoing person; laid-back person
Describes someone who is relaxed, unhurried, and not easily stressed. Often used affectionately or with mild criticism.
See also: のんびり
彼はのんびり屋だから、いつも遅刻する。
He's so laid-back that he's always late.
うちの猫は本当にのんびり屋で、一日中寝ている。
Our cat is a real easygoing type, sleeping all day.
From the adverb のんびり (leisurely, carefree) + 屋 (person with a certain trait). The exact origin of のんびり is uncertain, but it is a mimetic word.