>kuda - "where to" as a single word.
>
>If you don't know the archaic English words: whither, hither, thither, whence, hence, thence then you're in for a treat

I've met them before, and I think it's a shame (though nothing to put anyone to shame, just.. we'd say "it's a damage") that these aren't used.

>bolesnik - the afflicted?

That's "bolestan" - adjective. "Bolesnik" is a noun, denotes the afflicted person.

>inostranstvo - just "abroad" covers that

This is also a noun, not an adverb. "Putovanje u inostranstvo" - "a travel into abroad"?

>kvar - glitch?

Malfunction... but mechanical only. Haven't heard it applied to software yet. Also, "pokvariti" - break, cause to malfunction. But, "pokvariti se" (reflexive verb) is what perishable foodstuff does when it, well, perishes. Also means to become corrupt or spoiled, when applied to a person ("dubre jedno pokvareno" - literally, "trash one malfunctioning/perished" means "you rotten scum you").

>kvocka - rooster?

The lying hen, "kvocati" is "to make sound as a lying hen".

>najesti se - stuff oneself

That's "napuniti se". Also, you can't say to your guests, "don't tell me you have already stuffed yourselves, why don't you take cakes too"... while "najesti se" means just to have eaten enough (or much - depending on the intonation :).

>obuti se - to shoe. When one wears footwear one is "shod".

Ah, a horse. But then you don't have the word for "potkovati" - literally, to underforge, what one does when shoeing a horse, and "potkovica" - the underforged-thing, horseshoe.

>podatak - I use datum and data and sod those who don't understand.

So do I, but very few know it, and even fewer use it. But just going ahead and simply using the word may beat a path. Not impossible.