"One time wonder"

Question

I told my teacher that I wanted to start writing something for each class so that I could practice the stuff I was learning. Something like a diary if you will. Jokingly, she asked me if I was going to be a <Japanese phrase that I forgot> and when I asked her to explain she said that the phrase was used to describe people who say they are going to do something periodically but just do it once and then quit.

For the life of me I can't find what the term was in my notes. Does anyone know what I'm talking about?

Answer 1

She probably said [三日坊主]{みっかぼうず}.

三日坊主 literally means "three-day monk". It's a proverb/saying used to describe someone who can't stick to anything for a long time, or the act/situation of giving up one's resolution easily. I think this page explains the word beautifully: "It is used to describe people who start things with big promises and great enthusiasm, but never see them through to the end. A person who decides to get in shape, buys a $1000 membership to a health club and a new training wardrobe, and ends up training like gangbusters only to quit three weeks later would be a 三日坊主." For example, you use it this way:

• 日記をつけ始めたけど、三日坊主に終わった。
  I started to keep a diary, but ended up in 三日坊主. / gave up in a day or two.
• あの人は何をやっても三日坊主だ。
  He can never stick to anything.