What does it mean?
The anglicised form of the Gaelic O'Gallchobhair, meaning "descendent of Gallchobhar". This personal name is formed from the elements "Gall" meaning "strange or foreign" and "cabhair" for "help or support". It signifies descent from Gallagher who himself was descended from the King of Ireland who reigned 642-654. The motto for Gallagher is "Fidelity is my glory".
So what does it really mean?
DEFINITION: gallagher (vb, insensitive) to behave in contrary and over-emotional manner in a belief that this constitutes style or fashionability. Gallaghering is usually more dominant in the male of the species. Occurs at social functions such as concerts and awards ceremonies. After midnight, gallaghering almost always takes place in expensive hotel rooms (or occasionally an indoor swimming pool). NB it is impossible to gallagher without a journalist present and it may involve the over-consumption of alcohol, cocaine, ecstasy, men, women or chicken heads - or any combination thereof.
ORIGIN: after Rory Gallagher, blues guitarist (1948-1995); cf the brothers Gallagher (Noel and Liam) who play for the Status Quo revivalist band Oasis.
SYNONYM: parfitt, usually an older beast, often sporting a yellowish crest and tends to move at high speed - usually in tandem with Porschus Softopus.
ANTONYM: dion, to behave in contrary and over-emotional way whilst singing on stage (often in French). True gallaghers hardly move on stage and show little emotion.
USAGE: "Rod gallaghered in front of Parsons and the Loaded boys all night at the house."
FILE BETWEEN: galahad, a person characterised by nobility, integrity and courtesy, and gallivant, to gad about or flirt.