far vs furthest

far and furthest both are adjectives.

Word	Noun	Adjective	Verb	Adverb
far	No	Yes	No	Yes
furthest	No	Yes	No	Yes

far (adjective)	furthest (adjective)
located at a great distance in time or space or degree	(comparatives of `far') most remote in space or time or order
beyond a norm in opinion or actions
being of a considerable distance or length
being the animal or vehicle on the right or being on the right side of an animal or vehicle

far (adverb)	furthest (adverb)
at or to or from a great distance in space	to the greatest distance in space or time (`farthest' is used more often than `furthest' in this physical sense)
remote in time	to the greatest degree or extent or most advanced stage (`furthest' is used more often than `farthest' in this abstract sense)
to a considerable degree; very much
at or to a certain point or degree
to an advanced stage or point