unfasten

From un- +‎ fasten.

• (US) IPA^(key): /ʌnˈfɑːs(ə)n/

• Audio (Southern England):

  (file)

unfasten (third-person singular simple present unfastens, present participle unfastening, simple past and past participle unfastened)

1. (transitive) To detach from any connecting agency or link; to disconnect.
   • c. 1596–1599 (date written), William Shakespeare, “The Second Part of Henry the Fourth, […]”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act IV, scene i]:

     He doth unfasten so and shake a friend.

2. (intransitive) To come unloosed or untied.

• undo

• do up
• button
• button up
• tie up
• zip
• zip up

• unbutton
• untie
• unzip

• “unfasten”, in The Century Dictionary […], New York, N.Y.: The Century Co., 1911, →OCLC.