According to my Shakespeare teacher, it means love-sucking worm.
The quote "O me! You juggler! You cankerblossom! You thief of love! What have you come by night And stoln my loves heart from him" is said by the character Hermia in William Shakespeare's play A Midsummer Night's Dream.
Insults are, Oberon: "Tarry rash wanton: am I not thy lord?" Demetrius: "For I am sick when I do look on thee." Demetrius: "I rather give his carcass to my hounds" Lysander : " Away you Ethiop!" Hermia:"You juggler.you cankerblossom" Helena: "Fie,fie, you counterfit, you puppet you!" Lysander: "Get gone, you dwarf, you minimus of hind'ring knotgrass made, you bead, you acorn."