0 someone who competes in a triathlon (= a race in which people swim, ride a bicycle, and run):
She was a competition swimmer and runner but wanted more, so she became a world-class triathlete.
The 32-year-old triathlete blames air pollution for triggering his asthma attack.
We can complete it step by step however long the road is and it can't be completed however short the road is if you don't even mark your footprint.