so far

Concise Oxford English Dictionary © 2008 Oxford University Press:
far/fɑː(r)/

▶adverb (further, furthest or farther, farthest)

• 1 at, to, or by a great distance.

• 2 a long way in space or time.

• 3 by a great deal.

▶adjective

• 1 situated at a great distance.

  ■ more distant than another object of the same kind.

• 2 distant from the centre; extreme.

– phrases
as far as

• 1 for as great a distance as.

• 2 to the extent that.

be a far cry from be very different to.
by far by a great amount.
far and away by a very large amount.
far and wide over a large area.
far be it from (or for) me to used to express reluctance.
far from tending to the opposite of (what is expected).
far gone

• 1 in a bad or worsening state.

• 2 advanced in time.

go far

• 1 achieve a great deal.

• 2 be worth or amount to much.

go so far as to do something do something regarded as extreme.
go too far exceed the limits of what is acceptable.
so far

• 1 to a limited extent.

• 2 up to this time.

(in) so far as (or that) to the extent that.

– origin OE feorr, of Gmc origin.