Extraneous things are not relevant or essential to the situation you are involved in or the subject you are talking about.
例句
We ought not to bring in extraneous matters in trying to find a basis for a settlement...我們努力尋求解決問題的基礎時，不應該牽扯進無關的事情。I can choose to ignore these extraneous thoughts or certainly choose not to act on them.我可以選擇無視這些無關的想法，當然也可以選擇不按這些想法行事。