a greater distance than before or than something else; a comparative form of 'far' [= further]:
We decided not to go any farther.
farther away/apart/down/along etc
The boats were drifting farther and farther apart.
a resort town farther up the coast
farther south/north etc
Two miles farther south is the village of Santa Catarina.
Most of them were locals, but some had come from farther afield (=a greater distance away).
if you do something farther, you do it more or to a greater degree [= further]:
We'd better investigate farther.
The police decided not to take the matter any farther (=do more about it).
! In spoken English it is more usual to use further.