Sickness and illness
1. Formality: After establishing the fact that both words are close in meaning, it is worth pointing out that one is used in more formal settings than the other.
This is due to the fact that the word ‘sickness’ has no proper medical definition.
The word ‘ill’ can be defined properly as ‘a negative condition with a cause which reduces one’s feeling of wellness or health’.
2. Common Usage: Colloquially, the word ‘sick’ can be used to mean a feeling of nausea or vomiting which a person experiences.
Sometimes, the word ‘ill’ is also used in this manner. Also, the word ‘sick’ can be used to convey a sense of thorough irritation at a person or thing.
This can be seen in statements like: ‘I’m sick of going to school’, or ‘I’m sick of him, already’.
3. Societal perspective: Sickness as a concept is most closely aligned to the perspectives a society or a community has on a particular condition or characteristic.
For instance, left-handedness is considered a sickness in some communities and not in others.
4. Indicative of malevolence: The word ‘ill’ can in some cases be denotative of evil and cruelty and can also connote an attitude of unpleasantness and harshness.
Hence, people speak of such things as ill-manners, ill-tempered people, and ill-treatment received at the hands of a person or group of persons.
5. Harm/Injury: The noun ‘ill’ as opposed to ‘sick’ can be used to refer to physical harm or injury sufferable at the hands of a person or thing. An instance of this is in the statement: ‘Go in my name, and he will do you no ill.’
6. General Malaise: The word ‘sick’ can connote a general malaise, pervasive distress, or misfortune that afflicts either a person, group of persons an entire community, or a nation.
Instances of this usage are: ‘how do we solve the ills of our nation?’
7. Long term/Short term: In some definitions, sickness is an ailment that occurs for the short term; while illness can occur for both short and long terms.
8. Substandard execution: A thing may be said to be ill if it is perceived not to be done; according to a reasonable standard or is done in a botched manner.
In Charles Dickens’s ‘The Haunted House’, the house was said to be ‘ill-built, ‘ill-planned, and ‘ill-fitted.
9. Hip-hop usage: The word ‘ill’ is a modern-day recognized hip-hop slang used to denote sublimeness in a singularly creative way.
The rapper Nas named his 1994 album ‘ill-matic’, used to denote supreme, badass skill.
Sometimes too, in hip-hop, the word ‘sick’ may be used.
10. Origin: While both words have extensive etymologies, going back centuries upon centuries; the word ‘ill’ can be traced to the Old Norse words ‘illr’ while the word sick is traceable to the Old English word ‘soec’.