Is selling or trading my World of Warcraft account a violation of the Terms of Service agreement?

Would I be in violation of the Terms of Service agreement if I were to buy, sell, trade, or give away my World of Warcraft account?

According to the terms of use, yes

Ownership/Selling of the Account or Virtual Items.

Blizzard does not recognize the transfer of WoW Accounts or Blizzard Accounts (each an "Account"). You may not purchase, sell, gift or trade any Account, or offer to purchase, sell, gift or trade any Account, and any such attempt shall be null and void. Blizzard owns, has licensed, or otherwise has rights to all of the content that appears in the Game. You agree that you have no right or title in or to any such content, including without limitation the virtual goods or currency appearing or originating in the Game, or any other attributes associated with the Account or stored on the Service. Blizzard does not recognize any purported transfers of virtual property executed outside of the Game, or the purported sale, gift or trade in the "real world" of anything that appears or originates in the Game. Accordingly, you may not sell in-game items or currency for "real" money, or exchange those items or currency for value outside of the Game.

Blizz will ban any account found to be sold or traded for financial gain. They will also ban the account of anyone related to the transaction. So, if you sell your account and start a new one, they will ban your new account as well.