Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
ob-lĭtesco, tŭi, 3, v. inch. n. [latesco], to hide or conceal one’s self (rare but class.): a nostro aspectu oblitescant, Cic. Univ. 10, 33: ne in rimis (areae) grana oblitescant, Varr. R. R. 1, 51, 1: qui velut timidum atque iners animal metu oblituit, Sen. Ep. 55, 5; id. Q. N. 7, 29, 3.