He felt again that rush of controlled euphoria, that heady sense of purpose in destruction.
…than he could make out anything around him, he saw a towering building, a grim fortress, jet-black and forbidding: Voldemort’s thoughts had suddenly become Razor-Sharp again; he was gliding toward the gigantic building with a sense of calmly euphoric purpose… So close… So close… With a huge effort of will Harry closed his mind to Voldemort’s thoughts, pulling himself back to where he sat, tied to Ron, Hermione, Dean, and Griphook in the darkness, listening to Greyback and Scabior.
There are no more uses of "euphoria" in the book.
Show samples from other sources
She’s been euphoric since they started dating.
Endorphins reduce pain and, in the absence of pain, can induce euphoria.