adjective
torturous
TOR-cher-us/tˈɔrtʃˌuʌs/
Causing extreme pain or distress.
The runner grips his calf in torturous pain.

Etymology
Tortura originally meant twisting or writhing, then came to mean inflicted pain. With the adjective ending, torturous describes something characterized by torture, extending to experiences that cause great suffering or difficulty.
In context
it's a horrible death for many reasons one is it's slow and very painful so it's a torturous death
More examples
- They endured a torturous wait for news.
- The steep climb became torturous in the heat.
- His recovery involved months of torturous pain.
Forms
torturous · more torturous · most torturous