Found 3 items, similar to regretfully.
English → Indonesian (Kamus Landak) Definition: regretful sedih
English → English (WordNet) Definition: regretfully regretfully adv : with regret (used in polite formulas); “I must regretfully decline your kind invitation”
English → English (gcide) Definition: Regretfully Regretful \Re*gret"ful\ (-f?l), a. Full of regret; indulging in regrets; repining. -- Re*gret"ful*ly, adv. [1913 Webster]