Liis@paarthurnax,
Really? Where?
http://www.primagames.com/games/elder-scrolls-v-skyrim/primaguides/292/gameplay/8311/1
http://www.uesp.net/wiki/Skyrim:Whirlwind_Sprint
This is the only occurence of the word. Note its use as the possessive verb "to have," not the tense-forming one that lost should be.
William Congreve doesn't exist in The Elder Scrolls universe as far as I'm aware, so ignoring the reference, here are some possible explanations:
- Loost is a more formal version of lost, thus "hath" is given as the closest translation.
- Loost is a conjugation of lost specific to third person singular, and "hath" is given as the closest translation (rather than "has") to evoke a sense of archaism.
- Loost is a mistake on the part of the Nord who wrote this particular Word Wall, or is specific to a Nordic adaptation/dialect of the language.
With only one occurence, it's hard to say what exactly it is meant to be. It's there, and it's canon, so it's in the dictionary to stay. On the flip side, I wouldn't recommend using it until we understand more about where loost comes from.