Meaning:
Its source is Cinneidigh, a Gaelic name meaning "Helmet head."
Narrative:
This surname might have originated as the nickname of a hard-headed warrior. However, its use as a personal name in modern times can probably be attributed to the Kennedys of Massachussetts, a family prominent in American politics for three generations.
Especially honored by the use of the name are John F. Kennedy, murdered in 1963 during his first term as President, and his brother Bobby Kennedy, murdered in 1968 while campaigning for the presidency.