"Though" is similar to "but" and "however". It is usually used at the end of the sentence in spoken English:
I have a pilot's license. I haven't flown in almost 5 years, though.
In written English, it's more appropriate to use it between clauses:
I have a pilot's license, though I haven't flown in almost 5 years.
"However" can be used in the same way:
I do agree with the Prime Minister on defense, however.
"Though" is more casual than "however", though.