Could you please provide an example sentence for each adjective so that to show a situation when only one of the adjectives may be used while the others may not?
The thing that confuses me most is that the Longman Dictionary of Contemporary English defines these words like so:
First, it says something like "not a generous person":
- stingy: "informal not generous, especially with money"
- "a miserly person is not generous and does not like spending money"
- frugal: "careful to buy only what is necessary"
Then, it gives a second definition which boils down to "a small quantity":
- "a stingy amount of something, especially food, is too small"
- "a miserly amount or quantity is one that is much too small"
- "a frugal meal is a small meal of plain food"
So, "frugal" does stand out in a sense that it is mostly about food. However, all the three adjectives look way too similar. What's worse, they translate into exactly one in my native language.
Best Answer
First of all, frugal is not "mostly about food."
Second, the differences between the words should be apparent from dictionary definitions, but in case they're not:
Stingy and miserly are both pejorative. Frugal is usually used in a complimentary sense when applied to a person, and is neutral when describing an object (such as a "frugal meal").
Stingy is less severe than miserly. To call someone miserly is to make an extreme judgement about that person.