粗心 (cū xīn) literally means 'coarse heart' — combining 粗 (cū, 'rough, coarse') and 心 (xīn, 'heart' or 'mind'). It describes a mental state where attention is scattered or insufficient, leading to oversights, mistakes, or forgetfulness. Unlike words for deliberate negligence, 粗心 implies unintentional inattention — someone who rushes, daydreams, or fails to double-check details.

This adjective is commonly used to describe people ('他很粗心'), behaviors ('粗心大意'), or specific errors ('因为粗心写错了字'). It often carries a mild, slightly sympathetic or admonishing tone — not harshly judgmental like 'negligent', but more like 'absent-minded' or 'sloppy in focus'. It frequently appears in educational, workplace, or daily-life contexts where precision matters: exams, instructions, receipts, or household tasks.