Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
* frusto, āre, v. a., to break to pieces: cum Punicae praedae omnibus promontoriis insulisque frustarentur et fluitarent, etc., i. e. the booty taken from the Carthaginians went to wreck and was driven in pieces on the promontories, Flor. 2, 2, 32 (so acc. to the conjecture of Salmasius, Graevius, and others, instead of the common and certainly false reading, frustrarentur. N. Heinsius proposes eructarentur; v. eructo, II.).