Time for serious contemplation once again about the flourishing pandemic. A recent essay entitled the nose knows has been submitted for your erudition. Loss of the sense of smell, which sensation is called olfaction, is called anosmia. Hyposmia is a milder form of diminished olfaction.
Interestingly, smell sensation, technically olfaction, is a symptom preceding many Parkinson disease case cases. It is also a precursor to Alzheimer's disease.