A formal closing used at the end of a letter (usually paired with 拝啓 at the beginning); roughly equivalent to 'Yours sincerely'.
ビジネス文書では、冒頭に『拝啓』、末尾に『敬具』を使うことが多い。
In business letters, it's common to start with '拝啓' and end with '敬具'.
親しい相手には堅苦しいので、メールでは必ずしも敬具を使わない。
It's formal for close acquaintances, so you don't necessarily use 敬具 in emails.
手紙の最後に「敬具」と書いて封をした。
I wrote '敬具' at the end of the letter and sealed it.