1. A person who lacks initiative.
2. A person who lacks wherewithal.
3. A person who has no "sack." Lacks braveness, boldness, assertiveness.
1. The sackless intern can't seem to find any work to do.
2. That sackless chap wants to own a convenience mart, but can't even pay his newspaper bill on time.
3. It's a sackless captain that can't steer his own ship.