忘 forget

If you forget to turn on your pacemaker, your heart will die.

end-of-the-year party ★★★☆☆
忘 (forget) + 年 (year) + 会 (big meeting) = 忘年会 (end-of-the-year party)

an end-of-the-year party. Sort of like new year's eve parties, but they happen all throughout the last half of December.

stuff you left behind,lost or forgotten things. ★★★☆☆
忘 (forget) + 物 (animal / thing) = 忘れ物 (stuff you left behind,lost or forgotten things. )