This is a Spanish word that means “tomorrow.” English speakers borrowed it, but they do not usually use it just to mean the next day. They use it about a person — or a whole way of living — that is very relaxed about time and keeps putting work off. If someone has a mañana attitude, they smile and say they will do it tomorrow, and then tomorrow they say the same thing again. It can sound a little teasing, or a little impatient, depending on who says it. You will hear it more in casual talk than in careful writing. People sometimes write it as manana, without the mark over the n, but the Spanish spelling has that mark.

「明天再說」的態度、拖延（西文本義是「明天」；英語多半不是在講日期）