Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
ob-sŏpĭo, īvi, or ĭi, ītum, 4, v. a., to put or lull to sleep (post-class.): a somni tempore prohibere, ne obsopiantur, Scrib. Comp. 180: somno obsopitus, fallen asleep, Sol. 12: odoris novitate obsopitus, made faint, stupefied, id. ib.