- an employee in any of a number of professions considered to be essential to the functioning of society, for example teachers, police officers, health workers, shop workers, etc
- a person who works with a particular group of clients or patients and has a degree of responsibility for their welfare
Collins Concise English Dictionary © HarperCollins Publishers::
key worker, keyworker /ˌkiːˈwɜːkə/ n Brit