Not using or containing expressions natural to a native speaker of a language.
不地道的，不符合表达习惯的
Example sentencesExamples
Describing Miss Banner's misfortune, Miss Moo says that ‘she grew many kinds of sadness in her heart’, an unidiomatic and somewhat poetic expression that suggests at once foreignness and aestheticism.
If we could imagine a perfect language, we should suppose it would contain a mode of signifying the contrary of every name: this indeed our own language may be said to have, though sometimes in an awkward and unidiomatic manner.
This was evidenced in the format and style used for presenting ideas (semantic level), as well as in the use of unidiomatic language not following cultural conventions of the English language (pragmatic level).
I mentally note some unidiomatic turns of phrase, this time on English efforts by graduating classes in the Foreign Languages school, but am again shy enough not to correct them.
Why does a conductor so fastidious and precise with an orchestra always seem so blithely undisturbed by such unidiomatic, out-of-tune singing?