What is the X in X-mas?
mid-14c., "doing no evil, free from sin or guilt," from Old French inocent "harmless; not guilty; pure" (11c.), from Latin innocentem (nominative innocens) "not guilty, harmless, blameless," from in- "not" (see in- (1)) + nocentem (nominative nocens), present participle of nocere "to harm" (see noxious). Meaning "free from guilt of a specific crime or charge" is from late 14c. The earliest use was as a noun, "person who is innocent of sin or evil" (c.1200). The Holy Innocents (early 14c.) were the young children slain by Herod sfter the birth of Jesus (Matt. ii:16).
innocent in·no·cent (ĭn'ə-sənt)
Not apparently harmful; benign.