pathetic
So weak or poor that it makes people feel pity.
Pathetic means so inadequate or unsuccessful that it inspires pity or even contempt. When something is pathetic, it's so weak or ineffective that it makes you feel sorry for whoever's responsible. A pathetic excuse is one that's so flimsy nobody will believe it. A pathetic attempt at something is so feeble it barely counts as trying.
The word carries a sting. If your older brother calls your effort to beat him at chess “pathetic,” he's saying you played so poorly it wasn't even a real contest. When a villain in a story makes a pathetic last stand, they're defeated so thoroughly it's almost sad to watch.
Calling someone or their efforts pathetic is harsh and can be cruel. The word can point out when something truly falls short, but it can also be used just to tear someone down.