Frequenter is a related term of habitue.
As a noun frequenter
is a person who frequents; a regular visitor.
As an adjective frequenter
is (rare) (frequent
As a verb habitue is
A person who frequents; a regular visitor.
* more frequent (more common)
One who frequents a place; a denizen or regular
*:At half-past nine on this Saturday evening, the parlour of the Salutation Inn, High Holborn, contained most of its customary visitors.In former days every tavern of repute kept such a room for its own select circle, a club, or society, of habitués , who met every evening, for a pipe and a cheerful glass.