This is the 909th most frequent Japanese word.
楽
"楽" means "comfort," "ease," or "enjoyment."
In this case, '楽' is used in the context of enjoying or feeling pleasure from an activity.
旅行中に楽しい経験をしました。
I had an enjoyable experience while traveling.
In this sentence, '楽' conveys a sense of comfort or ease.
この椅子は座っていてとても楽だ。
This chair is very comfortable to sit in.
Here, '楽' describes something being easy or requiring less effort.