From here in the US, "Eldy" sounds like a patronizing or even insulting term to call an older person. Is it acceptable in the UK and EU?
I am an American who has lived in the UK for 36 years and am 73 years old. I have never heard the term "eldy" used in the UK or the EU.
The political-correctness brigade is starting to have an impact here, so there is some divided opinion and confusion about what terms are insulting, acceptable etc.
Ignoring all that, in day-to-day conversation and usage among ordinary people, the most commonly used terms are:
1. OAPs. Stands for "old age pensioners" and is still the most commonly-used term. Technically this means 60 for women and 65 for men (the age of the woman will gradually rise to 65 between the years 2010 and 2020) but is also a general term that people use to denote older people. It doesn't carry any emotional baggage but is a statement of fact.
2. Seniors. This is becoming more commonly used and doesn't carry any overtones of frailty or reduced physical/mental abilities.
3. Concessions. A term used when listing admission prices, where reductions are available for OAPs, but also for others such as the unemployed and disabled.
4. Elderly. This does have some faint overtones of impaired faculties. American visitors to the UK are shocked/amused when they see a roadside warning sign (see attachment) with the text "Elderly People". Seniors groups tend to object to it, but the Department for Transport is resisting efforts to drop it.
I personally am happy to be called an OAP or a Senior but would rather not be called "elderly" or "eldy" and, of course, am always happy to accept a concession on an admission price!