tazz · verb1
Unknown, though questionably related to North Yorkshire tazzed (“overmatched, defeated, beaten, unable to accomplish one's end”, adjective) recorded circa 1870. The proposed sense development would be someone who has been passed by another, faster competitor in race (who is tazzing) is therefore tazzed.
tazz · noun2
Possibly related to tazzle.
Etymology from Wiktionary, CC BY-SA 4.0.