A "pending" item is actively in process or awaiting action. "Outstanding" is a broader idea that merely means action is possible. An outstanding item can remain outstanding forever. A pending item is always outstanding, but an outstanding item might not be pending. In fact, it can even be forgotten. I'm not sure how "hang" fits in with this.

"hang" relates to suspending or delaying, "pending" refers to something awaiting a decision or resolution, and "outstanding" pertains to something unresolved or exceptional."hang" relates to suspending or delaying, "pending" refers to something awaiting a decision or resolution, and "outstanding" pertains to something unresolved.