verb/lɛ.se tɔ̃.be/
to physically drop (an object); to drop, to forget about, to leave; to give up; to let down or fail (somebody or something)
“Quand elle a laissé tomber son verre, il éclata en mille morceaux.” — When she dropped her glass, it shattered into a thousand tiny pieces.
Literally, “to let fall”.