adjective
rancid
RAN-sid/ˈrænsɪd/
Having an unpleasant smell or taste from spoiled fats or oils.
The cook recoils from the rancid butter in the dish.

Etymology
Latin rancere described being spoiled or rotten, so rancid names the offensive smell or taste of decay. The same verb also underlies rancor, where physical foulness became emotional bitterness.
In context
microwave. So like all the fumes get infused inside of my food. No wonder it makes sense now. It always had this like like trash kind of taste like this rancid taste.
More examples
- Keep the oil away from heat so it doesn't turn rancid.
- Rancid butter gives the cookies an unpleasant taste.
- These chips taste rancid even though the bag is unopened.
Forms
rancid
rancidity noun — The foul smell or taste of spoiled fats.