Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
1. rĕtento, āvi, ātum, 1, v. freq. a. [retineo], to hold back firmly, to keep back, to hold fast (rare; not in Cic.).
2. rĕ-tento (-tempto), āvi, ātum, 1, v. a., to try or attempt again, to reattempt (a poet. word of the Aug. per.): timide verba intermissa retentat, Ov. M. 1, 746: preces, id. ib. 14, 382: fila lyrae, id. ib. 5, 117: referoque manus iterumque retento, id. H.10,11: viam leti, id. M. 11, 792: studium fatale, id. Tr. 5, 12, 51: arma, Luc. 2, 514: memoriam meam, Sen. Ep. 72, 1: nec audent ea retentare, quorum vitia retractando patescunt, id. Brev. Vit. 10, 2: nec vana retentet spes Minyas, move or affect again, Val. Fl. 5, 679.
With inf.: saepe retentantem totas refringere vestes, Ov. M. 9, 208.