Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Ophir, indecl. (= [??]), a region in Southern Arabia, Vulg. 3 Reg. 9, 28; id. 1 Par. 29, 4.
Hence, Ophirius, a, um, of or from Ophir, Plin. 36, 26, 66, § 193.