Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
ex-aptus, a, um, adj., fastened (very rare): exaptum pendere onus ingens, Lucil. ap. Non. 235, 7; cf.: ex quo orbe pendeant exapta catenis tintinabula, Varr. ap. Plin. 36, 13, 19, § 92; so Fronto Fer. Als. p. 213 Mai.