protophilicity 

https://doi.org/10.1351/goldbook.08199
Special case of nucleophilicity, describing the relative rates of reactions of a series of Lewis bases with a common Brønsted acid. This term has the advantage over the commonly used "kinetic basicity" that philicity and fugality are associated with kinetics, while acidity and basicity are associated with thermodynamics.
See also: protofugality
Source:
PAC, 2022, 94, 353. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 2021)) on page 488 [Terms] [Paper]