They may be able to be expressed, but requiring a paragraph of text to explain. For an obvious example, take the word jihad. It doesn’t simply translate to “holy war”, but refers to the struggle for purity and righteousness. Most would consider this to be conducted primarily personally, but many both now and in the earliest years expand it to a crusade to spread the true faith and cleanse the world of the unrighteous, i.e. the current common usage in English.
Most languages have things like this, including English. Take a relatively simple word that just came to mind, agony. It could be translated simply as “pain”, but it has special connotations of long-lasting, ongoing pain born out of overwhelming injury to the body or the soul. Not all languages have a word for that. Hell, most languages don’t have a word for “blue”!
As to Greek philosophy, you seem to have pivoted to religion instead, but would be fascinated to know more about this ‘essentially meaningless’ concept. I wonder if that’s how the English-speaking members of those churches see it.
I don’t claim to be an expert, but in the past ~100 years or so they’ve moved towards coming back into communion, having realized that their theological differences are largely unimportant, so you can ask them.