noun, noun or participle which takes 'suru', transitive verb
respectfully written; written with respect
Formal, often used in letters or documents to indicate that the writer has composed the text with respect and care. Can be used as a noun or as a suru-verb.
この手紙は謹書したものです。
This letter was written with respect.
謹書の上、お送りいたします。
I will send it after writing it respectfully.