slipshod
Done in a lazy, messy, and careless way.
Slipshod means done carelessly or without proper attention to quality. When work is slipshod, it's messy, incomplete, or full of mistakes because someone rushed through it or didn't try their best.
A slipshod book report might have spelling errors, missing pages, and sloppy handwriting. Slipshod carpentry might leave gaps between boards or nails sticking out. When a contractor does slipshod work on a house, they might skip important steps or use cheap materials, creating problems that show up later.
The opposite of slipshod is meticulous or careful. Think of the difference between a chef who precisely measures ingredients and follows each step, versus one who just tosses things together and hopes for the best. A slipshod science experiment might produce unreliable results because the student didn't follow the procedure carefully.