Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
prae-vexātus, a, um, Part. [vexo], ill-treated, abused, or impaired previously or very much (post-class.): aeger viribus praevexatus, Cael. Aur. Tard. 1, 1, 18: praevexatae vires, id. Acut. 2, 32, 166.