frequentissime
frequentissime is a Latin form of frequens, meaning “crowded, in great numbers; frequent, repeated; (frequenter) often”. It is the superlative adverb.
Found 50 times in the Latin texts on Socratos.
Where it is used
Cicero, In C. Verrem 2.4.119: … cha nominata est; in qua gymnasium amplissimum est et complures aedes sacrae, coliturque ea pars et habitatur frequentissime. quarta autem est quae, quia postrema coaedificata est, Neapolis nominatur; quam ad summam theatrum maximum, …
All forms of frequens (declension table)
Source: Socratos (socratos.org), a free reader for Ancient Greek and Latin. Grammar from the Perseus Treebank and Morpheus; dictionary entries from Lewis & Short, A Latin Dictionary (Perseus Digital Library, CC BY-SA). Counts are from the texts on Socratos.