What is the difference between 楽天 and 楽観?

Question

When looking through jisho.org after reading some NHK News Easy articles, I came across 楽観{らっかん}, which seems to imply optimism in terms of outlook. However, 楽天{らくてん} also carries the definition of optimism, but I'm not quite sure what the difference between the two is other than the fact that Rakuten tends to refer to the company more often than not and that 楽観 is associated with 悲観{ひかん} as an antonym.

A similar situation exists for the 的 forms of all three of these, where 楽観的{らっかんてき} and 楽天的{らくてんてき} both generally mean 'optimistic', though Jisho also notes that 楽観的 also implies 'hopeful'.

What exactly is the difference between these two when it comes to usage?

Answer 1

楽天 is about one's personality or easy-going way of living, and it is typically used as part of a longer compound, 楽天家 (optimist). On the other hand, 楽観 is mainly about one's way of viewing on a specific issue.

When talking about someone's personality, 楽天家 and 常に楽観的な人 generally mean the same thing. When discussing specific topics like illness or sports matches, it's more appropriate to use 楽観.

From 明鏡国語辞典:

らくてん【楽天】

［名］物事をすべてよい方向にとらえ、人生を楽しく生きようとすること

らっかん【楽観】

［名・他サ変］ものごとの成りゆきをすべてよいほうに考えて心配しないこと。将来に明るい見通しをもつこと。「事態を楽観する」「楽観を許さない病状」「楽観的な見方」「楽観視」

See 人生 in the definition of 楽天. Also note that only 楽観 works as a suru-verb.