The concept is precise and can be communicated no matter what words are used.
Well, I hope then that what you are calling "concept" is a functional identification rather than some absolute ideal of tomato in itself.
Why? partly because language is context sensitive. There is the edible fruit that grows on plants and that we eat. But I could also ask you to select a tomato from a group of photographs, or plastic representations of food for instance. Do we ever know exactly what a tomato is? I don't think so. What we have is the ability to function in regards to tomatoes.
We can plant, harvest, purchase, slice, can etc. a tomato all the while not really knowing everything there is to know about it. If by concept you mean something like Plato's archetype of a tomato then I don't follow you.
If this functional usage is what you mean then literalism doesn't give you absolute knowledge but rather functional knowledge. Language as utility not as truth. My claim is that literalism occurs when people think that by naming something they have understood it and know it in some absolute total way. The belief that words can give one absolute certainty and assurance of knowledge is what I mean by the error of literalism.
lfen