Paradise
noun
This place has extreme comfort. It is paradise.
極楽 is a short for 極楽浄土 (the Pure Land in Mahayana Buddhism). While it might sound a bit old-fashioned, you can still use it to describe something heavenly. For example, if you're soaking in a cozy, relaxing hot spring, you could say, "Ahhh…極楽!"
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well. 極 has two on'yomi readings, though. So here's a mnemonic to help you remember which one to use:
In paradise, you meet Goku (ごく) from Dragon Ball Z. He grins and tells you he's taking a break from extreme battles and enjoying the extreme comfort of this heavenly paradise.
間違いで極楽に行った男についての小説が、映画化されました。
The novel about a man who went to paradise by mistake was made into a movie.