There are several epithets used for Siddhartha throughout the story.
Right in the very beginning of chapter one, Siddhartha is called "the young falcon," which implies strength, ferocity and keenness.
Later on, in the beginning of chapter three, he is called "the thinker," which identifies his preoccupation at that point in time with thinking about his place in the universe. He has just left his childhood friend, Govinda, with the Buddha and for the very first time in his life he is feeling alone. Later on in the same chapter he is called, "Siddhartha, the awakening one," as his thinking has led him to a revelation in which he feels "awakened."
an epithet of Buddha meaning “he who has attained his goal.”