How do we interpret?

When it comes to translations we find that synonyms sometimes don't make sense. Some translations are direct, some structured, and others are intuitive. In some languages of the east there is a lot of translation with words that don't necessarily go together. But when it comes to English there are many ways to say "happy," or, "sad." Sadness is a frown, happiness a grin, but where do they differ? Joy is something of a laugh, contentment is a soft smile, and bliss is a matter of beaming. Depression is a fake smile and tears (although not always at the same time), morose a deep frown without a smize, melancholy a sort of sickness in the eyes and mouth. The only thing that makes these things synonymous is that they're all about the same emotion. Quite literally the same but different, like leaves of different trees.

So, if a synonym is as simple as putting it in the same category of a word, what about words like "Immortality?" Where does it defer from "Universality?"

In the event of religious texts are we not to use the same laws in order to translate as we do with any other text? How many texts are incomplete? How many are not literally transliterated? How often do synonyms become obsolete and how does history show us the difference between the decisions of the day and the choices of the now?

So, with all that in mind (as well as the countless examples on earth): How do we interpret?