Though as conjunction or adverb?!

"The youngster who reads voraciously, though indiscriminately, does not necessarily gain in wisdom over teenager who is more selective in his reading choices."

Hello All,
What is the grammatical rule of "though"?!
I get confused whether it is adverb or conjunction according to the sources at the end of this post ?!
And what does whole sentence mean ?!

Though as Conjunction
http://www.ldoceonline.com/dictionary/though_1
2 used like 'but' to add a fact or opinion that makes what you have just said seem less definite, less important etc:

offenders were dealt with firmly though fairly.
Though as adverb
used especially at the end of a sentence to add a fact or an opinion that makes the previous statement less strong or less importantOur team lost. It was a good game though.

I think both conjunctive and adverb made sense when I was using both of them in the sentence
Thanks so much