also: のこりかす
Refers to the leftover, often worthless or unwanted part after the main part has been used or taken away. Can be used for physical scraps, sediment, or figurative remnants.
Please throw away the coffee grounds.
議論の後には、いつも感情的な残りカスが残る。
After the argument, there are always emotional remnants left over.
カス alone means 'dregs' or 'scum' and is more derogatory; 残りカス is slightly milder and specifically refers to what is left after something is finished.
Common mixed kanji-katakana spelling.
Hiragana variant; less common but still seen.
Uses the kanji 滓 (dregs); very rare and literary.
Uses the kanji 粕 (lees); rare and mostly for brewing contexts.
Compound of 残り (nokori, 'remainder') and カス (kasu, 'dregs'). The katakana spelling of カス is common for this word.