Strange, I can see your next post in my Inbox, but not here. Anyways, "jinoch" is much older, derived from root "jun-", the same way as English "young", German "jung" and Russian "юный".
Which reminds me of "junák", another archaic synonym.
Don't worry, all of them are undoubtedly masculines used for boys, not for girls.
It much (MUCH!) less archaic then Middle English (or Old Czech). It is in fact not archaic at all. It is bookish or dated but it still gets its use.
And hoch is even less "archaic". If anything, then it is dated/unfashionable https://en.wiktionary.org/wiki/Wiktionary:Obsolete_and_archaic_terms#Classifications_of_old_words but only in some contexts. You will hear "hoši" used quite often when cheering during sport.
I think it just means that it's a common Slavic root. For me as a Polish native "kluk" and "hoch" sound completely foreign and one wouldn't know what they mean as there is no similar equivalent in Polish, while the meaning of "chlapec" is obvious and instantly recognisable for us (even though our version of the word is slightly different).
hoch is a boy, not a young man (mladík, mládenec)
I would questions the translations of lad offered by the mentioned dictionary. Anyway, do not use simple translational dictionaries for these purposes (like learning words). At least when there are several possible translations. Often each of them is only valid in specific contexts. You need dictionaries that explain the words. Like what Merriem-Webster or similar do in English. When I learn English words, the said dictionary is not enough for me either.
Even though, to be fair, the definitions in the main dictionaries I checked do differ. The most recent one just says
hoch, -a m (6. mn. -ších)
chlapec, kluk: mají hocha a děvče; — expr. na shledanou, hoši!; naši hoši se vyznamenali sportovci ap.; — nemá dosud hocha;
so a boy (the same as kluk, chlapec), our boys our lads (for sportsmen and similar), a boyfriend
If you have the new male sound then that one is correct. If you have the old female sound then there is some extra noise in it, but the main consonant is correct too. Check the previous discussion here.
"hoch" is pronounced the say way as Scottish "loch" and the final co sonant is the same as in German "ch". Check our Tips and notes of the first lessons and try forvo.com for some recordings.