Definitions:

1. (comparatives of `far') most remote in space or time or order adjective
   • had traveled to the farthest frontier
2. to the greatest degree or extent, or to the most advanced stage adverb
   • My plan was developed farthest.
3. to the greatest distance in space or time (`farthest' is used more often than `furthest' in this physical sense) adverb
   • see who could jump the farthest

Synonyms:

• farthermost
• furthermost
• furthest
• utmost
• uttermost