Carious
/ˈkeriəs/
Definition 1 of 1
Pro Tip 1/3Medical Usage
The word 'carious' is primarily used in dental and medical settings to describe decay. 
During the check-up, the carious molar was spotted.
Pro Tip 2/3Technical Term
'Carious' is a technical term; use it with audiences familiar with medical vocabulary. 
The x-ray showed a carious lesion in the patient's jawbone.
Pro Tip 3/3Not Metaphorical
Unlike 'rotten,' 'carious' is not used metaphorically to describe non-dental decay. 
She is studying the effects of sugary foods on carious teeth, not on 'rotten' relationships.