Robustious and Unflappable

Robustious

Robustious adjective - Being rough or noisy in a high-spirited way.
Usage example: his buddies sent him off to the navy with many robustious and hearty toasts

Unflappable is an antonym for robustious.

Unflappable

Unflappable adjective - Not easily panicked or upset.

Robustious is an antonym for unflappable.
Cite this Source
Unflappable and Robustious. (2016). Retrieved 2026, August 14, from https://thesaurus.plus/related/robustious/unflappable
Robustious & Unflappable. N.p., 2016. Web. 14 Aug. 2026. <https://thesaurus.plus/related/robustious/unflappable>.
Unflappable or Robustious. 2016. Accessed August 14, 2026. https://thesaurus.plus/related/robustious/unflappable.
Google Ngram Viewer shows how "robustious" and "unflappable" have occurred on timeline