Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
sŭpĕr-impōno (-inpōno), no perf., pŏsitum, 3, v. a., to put, place, or lay upon (not ante-Aug.): saxum ingens, Liv. 39, 50, 3: statua superimposita, id. 38, 56, 3: manum, Quint. 1, 1, 27: allium, Cels. 5, 27, 6: cataplasmata, id. 3, 10: radicem arundinis, id. 5, 26, 35: superinposito linteolo, Plin. 31, 9, 45, § 103; Stat. S. 1, 1.