Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
assensor (ads-), ōris, m. [assentior], he that assents to or agrees with any one: cotidie commemorabam te unum in tanto exercitu mihi fuisse adsensorem, Cic. Fam. 6, 21; Auct. ad Her. 3, 23: vindictae, Val. Max. 6, 3, 6: irae, Sen. Hippol. 1207.