illness (n.)

• abnormality
• addiction
• affection
• affliction
• ailment
• allergy
• atrophy
• blight
• bug
• complaint
• complication
• condition
• defect
• deformity
• disability
• disease
• disorder
• distemper
• endemic
• handicap
• indisposition
• infirmity
• malady
• malaise
• morbidity
• morbus
• pathology
• rockiness
• seediness
• sickness
• syndrome