Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
tăgax, ācis, adj. [tago], that is apt to touch any thing; pregn., light-fingered, thievish (very rare): tagax furunculus a tangendo, Fest. p. 359 Müll.; cf. Non. 408, 33: manus, Lucil. ap. Fest. l. l. (Sat. Fragm. 30; 86): levis, libidinosus, tagax, * Cic. Att. 6, 3, 1.