Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
indūsĭum (in Varr. L. L. 5, § 131, written intusium), ĭi, n. [induo], a woman’s under-garment, Varr. l. l.: indusium est vestimentum, quod corpori intra plurimas vestes adhaeret, quasi intusium, Non. 539, 32; cf. indusium χιτωνίσκος, Gloss. Philox.