Tenzin is the leader of the Air Nation, the son of Avatar Aang, and one of the most important mentors of Avatar Korra. For a time, he was even the last airbender. His decades of airbending experience, skill, power, and sheer will make him one of the best fighters and benders in the series.
Tenzin is an airbending master, and correspondingly very skilled in all aspects of airbending.
While he isn't as powerful as his dad, he's still got some very respectable feats in this department.
Speed and Agility
Fittingly for a master airbender, speed is one of Tenzin's best attributes, and he is one of the fastest characters in the series.
While he may not look it, Tenzin is actually pretty durable.
Tenzin only had a couple of fights against named enemies, but his track record is still fairly good.
If you want to know more about the Red Lotus (who Tenzin has most of his feats against), I recommend checking out these two respect threads: