unpop

un- +‎ pop

unpop (third-person singular simple present unpops, present participle unpopping, simple past and past participle unpopped)

1. (transitive) To unfasten (a snap fastener).
   • 2003, Mair Rees, Drawing on Difference

     The sorts of activities I present are buttoning, lacing, popping and unpopping press-studs, dressing and undressing dolls - although the latter is not usually perceived at all as symbolic or 'play' but a merely mechanical activity.

   • 2008, Benjamin Parker, Leon Prilki (page 118)

     He sat the boy on his lap. And absently adjusted his clothes. In the boy's hand was a metal car. It was painted red. Leon reached down to his vest, unpopping the buttons that secured it beneath the nappy.

2. (transitive) To cause not to have popped.

   You can't unpop a balloon.

• uppon