Luó jí xìng is a noun meaning 'logicality' or 'logical consistency'—the quality of being logically sound, coherent, and well-structured. It combines three characters: luó (from luó jí, 'logic') and jí, which together form the loanword for 'logic'; xìng is a common noun suffix meaning 'quality' or 'nature', similar to '-ness' in English (e.g., 'happiness'). So luó jí xìng literally means 'the nature of logic'.

This word is frequently used to evaluate arguments, writing, explanations, or even everyday reasoning—especially in academic, professional, or analytical contexts. You’ll often hear it in feedback ('Your essay lacks logicality') or discussions about clarity and coherence. Unlike colloquial terms like tiáo lǐ (orderliness), luó jí xìng specifically emphasizes cause-effect relationships, valid inference, and structural integrity in thought or expression.