岳
ガク, たけ, おか, たか, たけん

point, peak, mountain

JLPT1 G7 S8 F1334

As per 丘# (hill) + 山 mountain → rugged, rocky *mountain* → *peak*. 嶽 and 岳 are distinct characters, but 岳 is the Shinjitai (new character form) adopted in Japan during the twentieth century to replace 嶽 for official use.

[Full Kanji Etymology List]