WE'RE FULL OF WHAT?

While randomly surfing, this morning, I ran across a horoscope website.  I never can resist looking to see what they say about my sign of Gemini.  Both BERT and I were born on the 23rd of May so we're both Gemini and this website said that means we're "Versatile, witty, creative and full of spunk."  I know we're versatile, witty, creative and full of something that starts with "s" but I'm not sure it's "spunk".