старший или старый а молодой или младший

Question

I asked these together because it didn't make sense (to me) to have two separate, but very related, questions...

I have some trouble with two sets of words (in the title). My two sources are https://en.wiktionary.org/wiki/%D1%81%D1%82%D0%B0%D1%80%D1%8B%D0%B9 and the book, https://slavica.indiana.edu/bookListings/textbooks/5000_Russian_Words - and unfortunately they do not explicitly state agreement in their usage.

Старший:

The book says,

elder, older; senior; (as noun) elder

and leaves the comparative out (but includes it in старый, and

Wiktionary says,

elder, older, senior
eldest, oldest
higher, highest
(substantivized, in the masculine, animate) foreman
(substantivized, in the masculine, animate) chief, man in charge
(substantivized, in the masculine, animate, military) first (lieutenant)
senior (suffix used for names of elders)

Старый:

The book says

old

Wiktionary says,

old
ancient, antique
olden

and includes comparatives from both words.

So Wiktionary doesn't really give great useage information and the book says that старее is used for "things and of old animate beings", while старше it says is used for "animate beings, not necessarily old ones".

1. So there really isn't a one-word solution in all uses?
2. How can старше be used for "not necessarily old ones"? As in young ones?! Contradictory?

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Младший

The book says,

junior; younger, youngest

with no mention of comparative.

Wiktionary says,

younger, youngest (in an earlier period of life)
junior

and gives the comparative, but no real useage.

Молодой

The books says,

young

but gives no specifics of its comparative, though it lists both.

Wiktionary says,

young
youthful
new

and gives its comparative, but no useage.

So the only available useage information comes from the book and says that младше is only for animate beings. Neither say anything about useage for молохе.

3. Can молохе be used in all contexts, therefore negating the need to use младше?

Answer 1

1. No, there isn't.

2. As in "Моя сестра старше меня на 3 года. Сейчас ей 14 лет". My sister is older than me but not old. Using "старее" in this case is inappropriate.

3. "Моложе" and "младше" are both used with animate beings. There isn't such a big difference between them as between "старше" and "старее".

Answer 2

2. How can старше be used for "not necessarily old ones"? As in young ones?! Contradictory?

Also as in being hierarchically senior, старше по званию

Младший - youngest

Not sure if it's correct. Youngest is ratherсамый младший/самый молодой, whereas младший is simply younger.

Otherwise the sentence у меня два младших брата wouldn't make sense as it would say i have two youngest brothers

3. Can моложе be used in all contexts, therefore negating the need to use младше?

Indeed both младше and моложе are being used with inanimate objects, although младше seems more frequent, but i personally still feel uneasy about this usage. I guess it's more pertinent to scientese and professional lexis than to general purpose language.

It's almost as using the English younger with inanimate objects.

If i had to choose a more fitting word i'd opt for новее/более новый - newer