Sacrilegious

Adjective

 * 1) Committing sacrilege.
 * 2) Acting or speaking very disrespectfully toward what is held to be sacred.

Thesaurus
aberrant, abnormal, abominable, apostate, atheistic, atrocious, backsliding, blasphemous, criminal, delinquent, deviant, disgraceful, disrespectful, evil, fallen, fallen from grace, hardly the thing, heretical, ignominious, illegal, impious, improper, inappropriate, incorrect, indecorous, infamous, irreligious, irreverent, lapsed, not done, not the thing, off-base, off-color, out-of-line, profanatory, profane, recidivist, recidivistic, recreant, renegade, scandalous, shameful, shameless, sinful, terrible, undue, undutiful, unfit, unfitting, ungodly, unlawful, unrighteous, unseemly, unsuitable, wicked, wrong, wrongful

Etymology
sacer: + lego:.

Trivia
Sacrilegious was the winning word at the 18th Scripps National Spelling Bee.