1. Not alert to what is potentially dangerous
   - unwatchful, unvigilant

See also: unwary

Antonym: alert

• osteomyelitis
• osteopath
• osteopathic
• osteopathist
• osteopathy
• osteopetrosis
• osteophyte
• osteoplasty
• osteoporosis
• osteosarcoma
• osteosclerosis
• osteosclerosis congenita
• osteostracan
• Osteostraci
• osteotomy
• ostiarius
• ostiary
• ostinato
• ostiole
• ostium
• ostler
• Ostmark
• ostomy
• Ostraciidae
• ostracise