Found 2 items, similar to unbutton.
English → English (WordNet) Definition: unbutton unbutton v : undo the buttons of; “unbutton the shirt” [ant: button]
English → English (gcide) Definition: Unbutton Unbutton \Un*but"ton\, v. t. [1st pref. un- + button.] To loose the buttons of; to unfasten. [1913 Webster]