far from; anything but; instead of
Used after a noun, adjective, or verb to strongly deny the preceding statement and often introduce a contrasting reality. The pattern is 'X どころか Y', meaning 'far from X, actually Y' or 'not X, but rather Y'.
Far from apologizing, he got angry instead.
let alone; not to mention; not only ... but also
Used to emphasize that if even the first (more likely or extreme) thing is true, then the second (less likely or more extreme) is also true. Often follows a negative statement or a rhetorical question.
Far from being rich, he's up to his neck in debt.
It's not cool at all; rather, it's almost hot.
He can speak not only English but French as well.
I'm so busy I can't even take weekends off, let alone a vacation.
I was so busy that, let alone eating lunch, I didn't even have time to drink water.
Far from speaking English, he can't even write it.
This dish was far from delicious—it was actually terrible.
どころではない looks similar to どころか but means 'this is far from the time/situation for X', not 'far from X, actually Y'.
どころ needs a negative predicate to mean 'far from being able to do', while どころか is a stronger stand‑alone contrastive particle meaning 'far from that, in fact...' and doesn't require negation.
どころか denies a weaker expectation to assert a stronger contrasting fact ('far from'), whereas まして extends a statement to a more extreme case ('let alone').
Derived from the noun 所 (ところ, 'place') + the particle か, originally meaning 'is it the place for ...?', which developed into a contrastive particle. The exact historical shift is uncertain, but the modern usage is firmly established as a grammatical particle.