Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
immūnītus (inm-), a, um, adj. [2. in-munitus], unfortified, undefended (rare but class.): oppida castellaque, Liv. 22, 11, 4: Sparte, Ov. M. 10, 169: inermes atque immuniti abscondimus, App. M. 8, p. 202 fin.: via, i. e. not properly made, impassable, Cic. Caecin. 19, 54.