If you want to refer specifically to the UK, you'll have to say UK citizens or UK residents. There is no adjective or demonym for political entities beginning with "United". As for your table, it's not entirely wrong, but it is a little misleading. The nouns ending in 'man' refer only to adult males. So, for example you cannot refer to a woman as an Englishman. You could say "Englishwoman", but it is not a term which is often used. In fact, all of these demonyms (nouns referring to a person's nationality) are quite old-fashioned. We tend to use the adjectival form in preference to the nouns, i.e. native speakers would say "My friend is English" rather than "My friend is an Englishman" "Briton" is quite a formal term. You may come across it in speeches and newspapers, but it would be fairly unusual for a British person to refer to themselves as "a Briton" in everyday contexts. Note that because "Briton" is a noun, you cannot add a 'the' to it to refer to the people as a whole. This rule only works with adjectives. "The British" refers to the entire nation, while "The Britons" seems suggest a specific group of British people. As for the weather... the answer you want is probably "mild", meaning that it doesn't get very cold in winter here. It's certainly mild compared with Ukraine. "Severe" doesn't seem right, and there is no such word as "droughty". I hope that helps.

It depends, but I call us "Brits". If we were watching football I might be English, Welsh, Irish, Northern Irish, Scots. The Britons is a bit odd as we might talk about "Ancient Britons" who were the "original" people (well probably not original but before the Romans) so talking about Britons is ok but not used much, which The British is good. WInters, these vary a lot but roughly "wet and cold" is how we describe them, to a person from Siberia, we would have wet and warm weather.