Scattered or fallen remnants/scraps left behind (literal, physical sense).
脱穀の際に、わらの落ちこぼれが残った。
During threshing, bits of straw were left scattered.
Leftovers, pickings, or remainders (small or discarded pieces used as pickings).
市場で落ちこぼれの果物を安く買った。
I bought leftover fruit cheaply at the market.
Colloquial (sensitive): a student or person who falls behind or cannot keep up with a group; a dropout or laggard.
彼は数学が苦手でクラスの落ちこぼれになってしまった。
He was bad at math and became one of the class slowpokes.
落ちこぼれと呼ばれるのはつらいので、もっと支援が必要だ。
Being labeled a dropout/loser is painful, so more support is needed.
社会の落ちこぼれという言い方は偏見を助長する。
Calling someone a 'dropout of society' fosters prejudice.