Disability is defined as the inability to perform all or part of one’s occupational duties because of an accident or illness.

Disability definition
Disability is defined as the inability to perform all or part of one’s occupational duties because of an accident or illness. It refers to an employees’s physical or mental impairment which has a substantial and long-term adverse effect on a his/her ability to carry out normal day-to-day activities.
This can be due to a sickness, injury or mental condition and is not necessarily caused by the job itself. Disability discrimination is incorporated into equality employment acts as it is illegal in most countries.