Costless
Costless adjective - Not costing or charging anything.
Unanswerable and costless are semantically related. In some cases you can use "Unanswerable" instead an adjective "Costless".
Unanswerable
Unanswerable adjective - Not capable of being challenged or proved wrong.
Costless and unanswerable are semantically related. Sometimes you can use "Costless" instead an adjective "Unanswerable".
Nearby Word: unanswered
Mutual synonyms
Cite this Source
Unanswerable and Costless. (2016). Retrieved 2026, July 21, from https://thesaurus.plus/related/costless/unanswerable
Costless & Unanswerable. N.p., 2016. Web. 21 Jul. 2026. <https://thesaurus.plus/related/costless/unanswerable>.
Unanswerable or Costless. 2016. Accessed July 21, 2026. https://thesaurus.plus/related/costless/unanswerable.
Google Ngram Viewer shows how "costless" and "unanswerable" have occurred on timeline