Alternative forms 
From Middle English thaugh, thagh, from Old English þēah (“ though, although, even if, that, however, nevertheless, yet, still; whether”), later superseded in many dialects by Middle English though, thogh, from Old Norse *þóh (later þó); both from Proto-Germanic *þauh (“though”), from Proto-Indo-European *to-. Akin to Scots thoch (“though”), Saterland Frisian dach (“though”), West Frisian dôch, dochs (“though”), Dutch doch (“though”), German doch (“though”), Swedish dock (“however, still”), Icelandic þó (“though”). More at that.
though (not comparable)
- (conjunctive) Despite that; however.
- I will do it, though.
- (degree) Used to intensify statements or questions; indeed.
- "Man, it's hot in here." — "Isn't it, though?"
- (despite that): all the same, anyhow, anyway, even so, in any case, nevertheless, nonetheless, still, yet
- Despite the fact that; although.
- Though it’s risky, it’s worth taking the chance.
- (archaic) If, that, even if.
- We shall be not sorry though the man die tonight.
Usage notes 
- (if): This sense is now archaic, except in the fixed expression as though.