Exculpate, absolve, exonerate, acquit, vindicate mean to free from a charge or burden.
Exculpate implies simply a clearing from blame, often in a matter of small importance.
Absolve implies a release, often a formal release, either from obligations or responsibilities that bind the conscience or from the consequences or penalties of their violation.
Exonerate implies relief, often in a moral sense, from what is regarded as a load or burden. In general exonerate more frequently suggests such relief from a definite charge that not even the suspicion of wrongdoing remains.
Acquit implies a decision in one’s favor with reference to a specific charge.
Vindicate, unlike the preceding words, may have reference to things as well as to persons that have been subjected to attack, suspicion, censure, or ridicule. As here compared (see also MAINTAIN ) it implies a clearing through proof of the injustice or the unfairness of such criticism or blame and the exoneration of the person or the justification of the thing.