Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Mătīnus, i, m., a mountain or promontory in Apulia, near the foot of Mount Garganus, now Matinata, Luc. 9, 185; Schol. Cruq. ad Hor. C. 1, 28, 3.
Hence,