A person who provides services to those engaged in a particular endeavor.
A civilian who follows an army, typically a family member of a soldier or someone who provides services to the soldiers, e.g. prostitution, sale of liquor, cooking and laundry.
One who joins a group, movement, or project without being a legitimate member; one who jumps on a bandwagon.
A person employed, especially by a social services department, to perform household chores and provide aid to a patient or infirm person in the latter's own home; a carer.
The aid provided by such people.