To waste time behaving in a foolish, silly, or frenetic manner. Said especially of or by children. "Spaz" is short for "spastic" and may be considered offensive due to that originally having been a derogatory term for someone with spastic paralysis or cerebral palsy. My friends and I just got really hyper eating a bunch of candy and spent the rest of the sleepover spazzing around. Let's go hang out up in my room. My little brothers won't be spazzing around up there.