noun
miso lees; miso dregs; miso strainings
The solid residue left after straining miso; a literal food term.
味噌汁を作ったあと、みそっかすが残った。
After making miso soup, miso lees were left.
noun
good-for-nothing; worthless person; left-out child
Colloquial, often used for a child who is excluded or treated as useless by peers; can also refer to any worthless thing or person. Sense 3 (child left out of games) is a specific common usage.
あの子はいつもみそっかすにされて、かわいそうだ。
That child is always treated as a good-for-nothing, poor thing.
グループで一人だけみそっかす扱いされた。
In the group, only one person was treated like a worthless outcast.
おちこぼれ refers to a dropout or someone who has fallen behind, often in an academic or social context, while みそっかす emphasizes being treated as worthless or excluded.
のけもの means an outcast or someone excluded, similar to the child-left-out sense of みそっかす, but みそっかす carries a stronger nuance of being considered worthless.
Compound of 味噌 (miso) + っかす (dregs/lees). The literal meaning 'miso lees' gave rise to the figurative sense of something worthless or a person treated as useless, similar to English 'dregs of society'.