Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Āverruncus, i, m. [averrunco], an averting deity: avertendo Averruncare, ut deus, qui eis rebus praeest, Averruncus, Varr. L. L. 7, § 102 Müll.; cf.: In istis diis, quos placari oportet, uti mala a nobis vel a frugibus natis amoliantur, Av[er]uncus quoque habetur Robigus, Gell. 5, 12, 14 Hertz.