well beiseds his badass helmet aromr, ship and plethora of wepons. he radiates badass true in the moves he dos very little but if you look into his backstory and history was well as the expanded universe youll find there plenty of stuff to back up his badassiveness.
on top of the hes DAMN good at his job(best in the galxy)he was the last of a warroer race. Darth Vader considered him to be the best bounty hunter in the Galaxy (in some instances, Fett was even to be referred to as Vader's "right-hand man"). Fett was aware of that opinion and it generally emboldened him to occasionally converse with the Sith Lord with a more confrontational tone that no one outside Emperor Palpatine or Grand Moff Tarkin would dare take with him. Fett was often found to be very cunning and witty like his father, but at a much more emphasized level. Throughout the many years of his bounty hunting career, Fett developed a strong sense of justice, moral obligation, and adhered to his own code of honor. He took only certain bounties that agreed with his own beliefs and brutal justice. But to those few, he whole-heartedly devoted all of his magnificent skill should the occasion call for it. This led him to believe in a quick, clean kill.
Fett was also an expert marksman and had access to considerable weaponry. Despite having this high-tech arsenal, he was not dependent on it. In his search for the Butcher of Montellian Serat, Fett had to capture him without his armor, equipped only with a bow, some arrows, and a crystal knife, due to electronic detecting equipment installed on the Devaronian's compound. He was dedicated to whatever job he was doing, and would often suspend grudges if it meant completing his mission. Also, during his time with the Clone Youth Brigade, he was able to shoot down all of the targets with one shot each on the Endurance, while the other members couldn't even hit the targets.
As a boy, he was much more enthusiastic and open-minded until his father's death at Geonosis. The death of Boba Fett's father at the hands of the Jedi named Mace Windu, inspired within Boba a deep-seated animosity against not only Mace, but all Jedi. But despite this, he seemed to have compassion for the rest of the Clone cadets, as he was shocked to find out that he had to abandon Jax, Hotshot, and Whiplash. The events following that tragedy shaped and scarred his life forever, resulting in a man who never went anywhere without his armor and weapons. He paid close attention to all details and double-checked his surroundings to calculate the best option to solve a problem. This helped Fett get the drop on IG-88 on Cloud City, who had placed a tracking device aboard Slave I prior to take-off to intercept Solo.
He had enough strength to hold Bossk, an infamous Trandoshan bounty hunter (whose species was known for its brute physical power) at bay. Very few in the Galaxy were as skilled in physical combat as he was. At one point, he even engaged Darth Vader in a personal combat, and while he did not exactly hold his own, his cunning enabled him to shoot Vader in the head (though unfortunately for Fett, because of his helmet, Vader was one of the few people this wouldn't work against) before Vader brought his considerable Force powers to bear.
basicly hes the perfect hunter with a code of honr that has become so rare in his chosen profesion...well that and a whole bunch more