Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
rĕbellātĭo, ōnis, f. [rebello], a renewal of hostilities, revolt, rebellion (post-Aug. for the class. rebellio), * Tac. A. 14, 31; Val. Max. 7, 3, 9 ext.; 7, 4, 1; Serv. Verg. A. 12, 186.