Definition of "regretfully"

regretfully

adverb
comparative more regretfully, superlative most regretfully
1. In a regretful manner, with regret.
  Quotations
  So after learning a great deal about iron founding and much more about pike fishing, one regretfully took leave of a shop full of kindly characters and proceeded to a worse lot of odours in the brass foundry.
  1944 November and December, A Former Pupil, “Some Memories of Crewe Works—II”, in Railway Magazine, page 343
2. (proscribed) Unfortunately, in a manner inspiring or deserving regret; used only as a sentence adverb (to introduce and modify an entire sentence).