Paddy

There are two definitions for Paddy:

• The word "paddy" is derived from the Malay word padi, rice plant. Hence Paddy field. (How far the farmers could throw their knives, dictated how much of the paddy field's crops they could tend/own)
• An informal, often derogatory, name for an Irishman [from Patrick]

The Irish version has several expressions and words connected to it :

Being in a Paddy

Throw a paddy: To become sulky or have a tantrum (paddy being a stereotyped 'stroppy' Irishman; presumably relating to the Irish resistance to British rule) It can be a racist slur.

Paddy wagon

Nickname given to a vehicle police use to transport prisoners. There were many immigrant Irish in New York after the potato famine. Many of them were poor and a lot were Police officers.

The name came from the New York Draft riots of 1863. The Irish were the poorest people in the city. When the draft was implemented it had a provision for wealthier people to buy a waiver. The Irish rioted, and the term Paddy wagon was coined.

  

Paddywhack

A policeman's truncheon or baton. Arose from the fact that the Irish were generally on the wrong side on the law in the New World and as such were often on the wrong end of the paddy whacker.