Deepen
Deepen verb - To make markedly greater in measure or degree.
Usage example: this book really deepens our knowledge of how the brain works
Extend is a synonym for deepen in expand topic. In some cases you can use "Extend" instead a verb "Deepen", when it comes to topics like make more intense, make depth greater.
Extend
Extend verb - To make longer.
Mutual synonyms
Cite this Source
Extend and Deepen. (2016). Retrieved 2026, August 15, from https://thesaurus.plus/related/deepen/extend
Deepen & Extend. N.p., 2016. Web. 15 Aug. 2026. <https://thesaurus.plus/related/deepen/extend>.
Extend or Deepen. 2016. Accessed August 15, 2026. https://thesaurus.plus/related/deepen/extend.
Google Ngram Viewer shows how "deepen" and "extend" have occurred on timeline