忘
ボウ, わす.れる
forget
JLPT3 G6 S7 F1129
As per 亡# (obscure) + 心 heart/emotions → obscure state of mind, in the form of forgetfulness or overlooking something → *forget*; *overlook*; *leave behind*. 忘 and 忙 are an example of a pair of characters devised from the same elements but expressing different meanings; for another example, see 含 and 吟.
[Full Kanji Etymology List]