poor writing; messy handwriting and composition
A humble, self-deprecating phrase used to apologize for one's own messy handwriting and disorganized writing, often in letters or notes.
I apologize for my messy handwriting and poor writing.
Please forgive my scribbling.
Compound of 乱筆 (messy handwriting) and 乱文 (disorganized writing), both using 乱 (disorderly). The exact historical origin is uncertain, but it is a conventional set phrase.