1. In an unattainable manner or to an unattainable degree
   - unattainably

See also: unachievable

• Onychomys
• Onychophora
• onychophoran
• onychosis
• onymous
• onyx
• onyx marble
• onyxis
• oocyte
• oodles
• oogenesis
• ooh
• oolite
• oology
• oolong
• Oom Paul Kruger
• oomph
• Oomycetes
• oooh
• oophorectomy
• oophoritis
• oophorosalpingectomy
• oops
• oops-a-daisy
• Oort