Old English hæsl, hæsel, from Proto-Germanic *hasalaz (source also of Old Norse hasl, Middle Dutch hasel, German hasel), from PIE *koselo- "hazel" (source also of Latin corulus, Old Irish coll "hazel"). Shakespeare ("Romeo and Juliet," 1592) was first to use it (in print) in the sense of "reddish-brown color of eyes" (in reference to the color of ripe hazel-nuts), when Mercutio accuses Benvolio:
Thou wilt quarrell with a man for cracking Nuts, hauing no reason, but because thou hast hasell eyes.