Usopp was the "Liar" of the group as in Japanese "Uso" ment lie or falsehood. In the villiage the Straw Hats found him Usopp was the liar of the town. When Usopp tried to warn his village that there were pirates, no one believe him.
Usopp has been stranded on the island of "No Return" where once you land on the island, you cannot get out. But he did with miraculous improvements. Some of his moves are listed here.
Flame Ball
Octopushoes
Usopp Noise (He takes out a chalk board and rubs his nails across it.
Usopp AAaaaAAAaaaAA! (He basically uses a grappling hook like Tarzan would use a vine and swing, screaming AAaaaAAaAaA!
Usopp Hop
Zombie-Purifying Salt Ball
Don't Cross This Line
Extra Large Freezer's Super Sub-Zero Freezing Cannon