1. Morally binding or necessary
   "it is incumbent on me to attend"

See also: irremissible, obligatory

• rattlesnake
• rattlesnake fern
• rattlesnake master
• rattlesnake orchid
• rattlesnake plantain
• rattlesnake root
• rattlesnake weed
• rattlesnake's master
• rattletrap
• rattling
• rattly
• rattrap
• Rattus
• Rattus norvegicus
• Rattus rattus
• ratty
• Rau-Sed
• raucous
• raucously
• raucousness
• Raudixin
• rauli beech
• raunch
• raunchily
• raunchiness