combining the English word
, which together have meanings such as "almost", or "very nearly", "to the point of, but not entirely." These should always be followed by a verb
or an adjective
which indicates a completed or extreme state.
all but exhausted -- very, very tired
all but impossible -- very, very difficult
This expression dates back to the 1600's, when English didn't really make a whole lot of sense
. It is still in use 400 years later, when English still doesn't make a lot of sense