unfastening is unfasten's Present Participle

unfasten

US [ʌnˈfæs(ə)n]
UK [ʌnˈfɑːs(ə)n]
  • v.放松;解开;松开
  • Web同本义;解开v;脱开
Simple Present:unfastens  Present Participle:unfastening  Past Tense:unfastened  
v.
1.
放松;解开;松开