Flap
Flap verb - To move or cause to move with a striking motion.
Undulating and flap are semantically related. In some cases you can replace term "Undulating" with "Flap", this verbs are similar.
Undulating
Flap and undulating are semantically related. Sometimes you can use "Flap" instead a verb "Undulating".
Cite this Source
Undulating and Flap. (2016). Retrieved 2026, August 13, from https://thesaurus.plus/related/flap/undulating
Flap & Undulating. N.p., 2016. Web. 13 Aug. 2026. <https://thesaurus.plus/related/flap/undulating>.
Undulating or Flap. 2016. Accessed August 13, 2026. https://thesaurus.plus/related/flap/undulating.
Google Ngram Viewer shows how "flap" and "undulating" have occurred on timeline