to drop something / to remove/take off / (impolite) to make a woman one's girlfriend / (Internet slang) to download / (informal) to fail an examination

落とす: to drop something

(computing) key / (music) key

key (tool for opening or locking something) / key; clue (important fact for solving something) / lock

key

he / distal demonstrative, something far off removed from both speaker and listener: that / boyfriend

distal demonstrative, something far off removed from both speaker and listener: that, yon / particularly, male personal third person pronoun: he / by extension from he: boyfriend

he; boyfriend

to become disheartened

to die (from accidents or disease)