noun, na-adjective
good correspondent; ready writer
Describes a person who writes letters or keeps up correspondence diligently. Often contrasted with 筆不精 (writing-shy).
See also: 筆不精
祖母は筆まめで、毎月手紙をくれる。
My grandmother is a good correspondent and sends me a letter every month.
彼は筆まめな人だから、すぐに返事が来るよ。
He's a ready writer, so you'll get a reply quickly.
Antonym: describes someone who is poor at or avoids writing letters.
Compound of 筆 (writing brush, writing) and まめ (diligent, healthy). The まめ part is often written in kana; the kanji 忠実 is ateji.