to write freely
... to think freely 畅想; 畅想 to write freely 信笔; 信笔 unable to move freely 行动不便; 行动不便 ...
Write Rough And Ready
doodle
holograph ; Personal letter ; autograph letter ; Art Mail
"信笔"是个多义词,它可以指信笔(汉语词汇),信笔(范成大诗作)。