register too low or too refined

In Other Words（Jhumpa Lajiri著）を読んでいます。
Yet the impulse to track down the right word remains irrepressible, so even in Italian I try. I check the thesaurus, I leaf through my notebook. I put in a new word, just read that morning in the newspaper. But my first readers often shake their heads, saying simply, "It doesn't sound right." They say the word I'd like to use is now considered dated, that it belongs to a register too low or too refined, that it sounds either precious or too coloquial (thus I learned the adjective aulico, lofty).

"register" はこれまでに2度（9/6/2011、5/31/2008） 異なる意味の "register" を取り上げていますが、今回の "register" は又別の意味・用法の様です。辞書を見ます。
・Oxford English Dictionary: A variety of a language or a level of usage, as determined by degree of formality and choice of vocabulary, pronunciation, and syntax, according to the communicative purpose, social context, and standing of the user.: Written language is often a special register, distinct from most styles of speech, and the information conveyed by writing and by speech is not identical.
・Collins Dictionary: In linguistics, the register of a piece of speech or writing is its level and style of language, which is usually appropriate to the situation or circumstances in which it is used.
・Cambridge English Dictionary: the style of language, grammar, and words used for particular situations: People chatting at a party will usually be talking in (an) informal register.