hypertonicity
noun
hy·per·to·nic·i·ty ˌhī-pər-tə-ˈni-sə-tē 
plural hypertonicities
: the condition of being hypertonic
especially : hypertonia
Example Sentences
Recent Examples on the Web Pelvic floor disorders happen when the supportive muscles in that area are either too tight (known as hypertonicity) or too weak and stretched out (known as hypotonicity). 
Claire Sibonney, SELF, 29 Sep. 2021
Claire Sibonney, SELF, 29 Sep. 2021 Word History
First Known Use
1886, in the meaning defined above
Medical Definition
hypertonicity
noun
hy·per·to·nic·i·ty -tə-ˈnis-ət-ē
plural hypertonicities
: the quality or state of being hypertonic