Here's a further contribution from Benjamin Geer on the subject of coining new words in Arabic. I'm quoting his email in full:
Take the word "toxic". In English, we can add bits to make "toxicology" and "toxicologist". Arabic, with its three-letter root system, can't do this. For "toxicology" you have to say "the science of poisons", while "toxicologist" becomes "a specialist in the science of poisons". Basically, it means adding whole words rather than syllables and the more technical it gets, the more cumbersome it is to express complex scientific ideas in Arabic.
Actually, the most common Arabic term for "toxicologist" is أخصائي سموم. It has the fewer letters than "toxicologist", and only six syllables as opposed to five, so it's hardly more cumbersome. Why does it matter that it's two words instead of one? And in this case, the meaning of the Arabic term is clear to non-specialists, whereas the meaning of the English term is not.
Another point is that the way new words are constructed in English results in concise terms with a very precise meaning, and little room for ambiguity. For example, "anaesthesia" and its related words have a very clear medical context in English, while the relevant Arabic roots, b-n-j and kh-d-r, are potentially more ambiguous because they have more general connotations
relating to drugs and narcotics.
All languages are rife with polysemy. You can always cherry-pick examples of words that are more precise in one language than their equivalents in some other language, but if you look at language overall, you find that polysemy is everywhere, and that technical terms often have a variety of more general meanings. A "ring" can be a circular piece of jewellery, a square space where boxing matches are held, a certain kind of algebraic structure in mathematics, or the structure of the molecules in certain chemical compounds. A "track" can be a strip of ground where races are held, a metal bar on which a train moves, or a sequence of sectors on a compact disc. A "head" can part of the human body, part of the hard disc in your computer, or part of a syntactic structure in linguistics. A "base" can be a military installation, the radix in an exponential expression in arithmetic, or a certain type of liquid in chemistry. None of these ambiguities poses the slightest problem in practice, because context enables us to identify the relevant meaning.
Obviously, some new English words need explanation, though many do not. Very often, a native speaker can quite easily work out what they mean without help from anyone else, or having to look them up in a dictionary.
Your example of "toxicology" shows that this happens in Arabic, too. However, I think that in reality, very few technical terms in any language are immediately comprehensible to someone without specialised training. I suggest you open a dictionary of technical terms in mathematics, medicine, computer science or physics, and see how many words you can understand without help.
Before making judgements about the ease or difficulty of coining technical terms in Arabic, I think you should talk to people who are actually doing it. In my fields (sociology and linguistics), I've found that Arab researchers are doing a very good job of translating the latest terminology into Arabic. In my view, their efforts demonstrate that, far from being cumbersome, Arabic is fully capable of expressing current scientific concepts in a straightforward and convenient way.
I won't respond at the moment, but it would be nice to hear some thoughts about this from native Arabic speakers.