Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
phărē̆trĭger, ĕra, ĕrum, adj. [pharetragero], quiver-bearing (poet.): clade pharetrigeri regis, i. e. of the Persian king Xerxes: regis, Sil. 14, 286.