The full forward at a football match I recently attended in Co Wicklow fell in the square, as we used to call it before the GAA commentators started to show their erudition and call it a parallelogram. He immediately appealed to the referee for a penalty.
He didn't get it, so he continued to sulk while sitting on his fud (see below), and was told by an enthusiastic female follower of the opposing team who was sitting alongside me, to "get up, you useless gaaby". A gaaby, she kindly informed me, was a stupid fool, a blockhead.
I afterwards found the word in the dialect dictionaries under gaby, which has, it seems, a variety of pronunciations in both Scotland and the English midlands. It is also found in the west of Ireland. Jane Barlow, interesting only for her use of western dialect, has "Entrusting so critical a task to a quare blundering gaby like Larry", in her Irish Idylls, published in 1892. Jane, would I feel, have pronounced the word "gaybe".
That's how I heard the word from a Sligo friend some years ago. Dickens, I note, has the word : "Little Dorrit . . . asked who it was, to which Fanny made the short answer, that gaby."
Some sources tentatively suggest the word is associated with gape, which has its origin in Old Norse gapa, to open the mouth as the stereotypical fool is said to do. Others have suggested the Icelandic gapi, a rash, reckless person. Oxford, I see, tends to discount this latter theory.
Fud is a word I've heard only in the north of Ireland. It means the tail or scut of a rabbit, but its use is extended : a footballer is laughed at for falling on his fud, and you may hear corner boys praise the shape of a passing female fud. Burns has "[they] pawned their duds/they scarcely left to co'er their fuds", in The Jolly Beggars.
This word, like gaby, has given the etymologists a lot to think about. Found in Ulster and in Scotland and in general dialect use in England, it is probably of Scandinavian origin. The Old Norse has futh (as close as I can get without their typeface), an obscene word which I will gloss as Latin femen to save my readers' blushes. Futh has been formally identified with the Sanskrit putau, buttocks, so in one form or another it has been around for a very long time indeed.