noun
original intention; beginner's resolve; initial enthusiasm
Common in set phrases such as 初心を忘れない and 初心に返る, referring to the fresh motivation or purpose one had at the beginning.
忙しくなっても、初心を忘れないようにしたい。
Even when I get busy, I want to make sure I do not forget my original intention.
失敗したときは初心に返
When you fail, it is important to return to your original motivation.
noun, noun which may take the genitive case particle 'no', na-adjective
inexperience; naivety; greenness
Less common in everyday speech than words like 初心者, 未熟, or うぶ. Used as a noun, の-adjective, or な-adjective for someone still inexperienced or innocently naive.
この入門書は、初心の読者にも分かりやすい。
This introductory book is easy to understand even for inexperienced readers.
彼は初心なところがあって、すぐ人を信じてしまう。
He has a naive side and tends to trust people right away.