so_far
1. [ adverb ] used in negative statement to describe a situation that has existed up to this point or up to the present time
Synonyms: yet as_yet heretofore thus_far up_to_now hitherto until_now til_now
Examples:

"So far he hasn't called" "the sun isn't up yet"

2. [ adverb ] used after a superlative
Synonyms: yet
Examples:

"this is the best so far" "the largest drug bust yet"

Similar spelling:   Soffer
  Soper
  sober