Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
vĭcissātim, adv. [vicis], in return, again (ante-class. for the class. vicissim): ad argumentum vicissatim remigrare, Plaut. Poen. prol. 46; id. Stich. 4, 1, 27; Naev. ap. Non. p. 183, 15.