Seeing a sling in your dream may indicate that changes are coming into your life. If you show a sling to someone who is ill, it could signify their transition to a new place or even death. The sling may also represent your release from the influence of a guardian or protector in your life. This dream could mark the beginning of new opportunities and challenges for you.
From Imam Muhammad Ibn Seerin's Dictionary of Dreams According to Islamic Inner Traditions â entry "Sling" (page 396) â resolved via the equivalent "Slingshot" entry.
Bringing a slingshot before a sick person in a dream means transporting him to a new place, or it could mean his death and burial. A slingshot in a dream also means removal of a guardian from his office, or recovering from drug addiction, or it may represent a messenger. Using a slingshot to cast stones at others in a dream also means rightly invoking a strong curse on them. If one sees a woman using a slingshot to throw stones at him in a dream, it means sorcery or witchcraft. A slingshot in a dream also denotes just and harsh words. Holding a slingshot and preparing to shoot in a dream represents one's strength and determination to say something just and true. If one carries a slingshot but adoes not use it to cast stones in the dream, it means that he will repent for his sin.
Note: Islamic dream interpretation depends on the dreamer's circumstances and state. This is a general guide drawn directly from the source book.