Definition: Anosmia is a medical term for an inability to detect smells due to the lack of olfactory receptors or pathways in the brain. It's often seen in individuals who have a genetic defect affecting these receptor cells or other factors that affect olfaction, such as smoking, exposure to certain chemicals, or autoimmune diseases. Anosmia can lead to difficulties in personal hygiene and social interactions, while it may be mild or severe depending on how badly affected someone is.