I have been watching Y Sioe Frenhinol every available minute. I watch in Saisneg because I want to know what is going on rather than improve my Cymraeg. I met a mystery (to me). On screen was listed the name of the class. But in some of the classes was a word I did not know. I was trying to work it out by ‘derivation’ but, in the end, got up, fetched my Geiriadur Mawr and looked. Not there!! I looked at the back where words were added in later editions. Not there. I looked under ‘animals’, Not there. Finally, despite still trying to watch TV, I grabbed my laptop, logged in and asked Google. “Gelding”. Well, that made perfect sense. I didn’t remember seeing the word ‘adfarch’ before, but I used to watch with subtitles, so maybe hadn’t noticed. I looked up ‘gelding’ in my geiriadur mawr and found ‘ceffyl’!! THAT is clearly a euphemism. It just means ‘horse’. I then tried my old, almost forgotten, little Collins dictionary from the '60s. ‘Adfarch’, not there, ‘gelding’ - ‘adfarch or ceffyl’!! I had begun to think I was dealing with some sort of prudish ideas dating from reaction to the Blue Book, but if it got in in 1960, why not in bigger, better dictionary updated in 2012? Why only in the Enlish-Welsh section? Any ideas? Any similar experiences?
It’s in http://www.geiriadur.net (U. Wales, Trinity St David)
(I find it sometimes has words in that http://geiriadur.bangor.ac.uk doesn’t have, for example ).
A gelding is a male horse which has been castrated.
For some reason, that brings to mind an expression which you will hear at certain intervals at Wimbledon.
I did actually know that! I didn’t know the word ‘adfarch’ meant that because I’d never actually wanted to say it in Cymraeg!! If I happened to want to describe my favourite riding horse I would say, in English, “He was a beautiful grey gelding!” But I didn’t mix with ‘horsey’ people who spoke Cymraeg! So, “Roeth e …er what’s ‘gelding’??”, never passed my lips!! I did ask about ‘bitch’ and was told not to say ‘gast’ as it was VERY rude! I objected that my canine friends were both female and obtained the concession that, when talking to a breeder, ‘gast’ was permitted. It is in both my dictionaries!!
To Mike: So why is St. David’s less prudish than Bangor?? Does Bangor have ‘gelding=ceffyl’? Or is the actual meaning of ‘adfarch’ irrelevant as to why it got left out this way?
I see the Geiriadur has some alternatives.
gelding n. [-]
adfarch m (adfeirch), ceffyl disbaidd (a gelded horse) m (ceffylau disbaidd), S.W: rhagfarch m (rhagfeirch)
Yndy. (or “oes”, perhaps)
Dim syniad. 
Maybe it’s not prudishness at all, but just that gogledd doesn’t use ‘adfarch’? I’ll send a pm to aran to check!!
I’d be really grateful if you’d only use private messages for urgent/private stuff - otherwise, just tag me by putting @aran and I’ll see the conversation (in fact, I see almost every conversation anyway, so just asking me will usually work) 
I don’t think I’ve ever heard anyone, anywhere, use ‘adfarch’ - but I don’t exactly move in farming circles, so I’m not the best person to ask about this
Sorry! Truly! Mae ddrwg iawn iawn gen i!! I truly thought they were for mailings of limited interest to others!!
As for ‘adfarch’, since the host county was Gwent, it may well be a ‘gogledd/de’ thing and I’ve been chasing…windmills? …red herrings???