That No Man...Defraud his Brother

According to BDAG the word translated "defraud" in the KJV (1 Thess 4.6) means: To take advantage of, outwit, exploit, cheat. While the context is of sexual sin, and it certainly has application to that, the broader application is to any number of things. For instance, selling your brother something that you know is worth much less than you sell it, like it is broken and you know it, but he does not. Cheating is similar, an example might be buying something from him that you know is much more valuable than what he is charging, but he doesn't know it.