1. In a random manner
   - randomly, indiscriminately, haphazardly, arbitrarily, at random, every which way 
2. Without having a choice
   - nolens volens

Encyclopedia: Willy-nilly

• octavo
• octennial
• octet
• octette
• octillion
• octo-
• October
• October 12
• October 24
• October Revolution
• Octoberfest
• octodecimo
• octogamy
• octogenarian
• octonary
• octopod
• Octopoda
• Octopodidae
• octopus
• octoroon
• octosyllabic
• octosyllable
• octroi
• octuple
• octuplet