Exculpate \EK-skuhl-payt\ or \ek-SKUHL-payt\ , transitive verb;
1. To clear from alleged fault or guilt; to prove to be guiltless; to relieve of blame; to acquit
This word dates to the 1650's and comes from Middle Latin exculpatus, which is the past participle of exculpare which derives from Latin ex culpa. Ex culpa is a combination of ex ("from") + culpa (ablative of culpa "blame"). Exculpated and exculpating are related to this word, exculpation dates to 1715 and exculpatory dates to the 1780's.
Today's word and the first definition were both taken from Dictionary.com's 'Word of the Day' for Tuesday, January 4
Etymologies come from the Oxford English Dictionary and/or Etymonline.com