General term for sickness or disease; can be used in both literal and figurative contexts.
He passed away after a long illness.
Figurative use referring to a personal flaw, vice, or deeply ingrained bad habit.
Gambling is his weakness.
He contracted a serious illness when he was young.
His spendthrift habit reared its head again.
My grandfather had suffered from a heart condition for many years.
She kept working while fighting her illness.
He suffered for a long time from an illness of unknown cause.
sick dog; rabid dog
feigned illness; pretended sickness