'Exonerated': or 'Within NYPD Guidelines' - the alleged conduct occurred but did not violate the NYPD's own rules, which often give officers significant discretion.
'Substantiated': The alleged conduct occurred and it violated the rules. The NYPD has discretion over what, if any, discipline is imposed.
'Unsubstantiated': or 'Unable to Determine' - CCRB has fully investigated but could not affirmatively conclude both that the conduct occurred and that it broke the rules.
Further details on conclusion definitions.