Which language has the most words?

There is no way to answer this question, because to answer it you have to count the Words in each language and then compare those numbers.

However there are problems with both parts of this -- with counting and with comparing.

Counting: In almost every language there are base forms that can be inflected, declined, and suffixed/prefixed any number of ways (for example: press, pressing, pressed, depressed, repressed, suppressed, oppressed, impress, etc) and many languages, like German, allow speakers to make new Words by combining existing Words. On top of that, speakers of living languages constantly add new Words to the language by invention and by borrowing, and older Words fall out of regular usage. So... how do you go about counting? It is just not possible make an accurate count.

Comparing: There are about 6500 languages in the world, but few of them have dictionaries of high quality like, for instance, the Oxford English Dictionary. So even if you wanted to make an approximation by looking at how many Words are in the best dictionaries, this effort will fail. You can't compare if you don't have similar things to compare!

It is widely assumed that English has the most Words, but even the Oxford English Dictionary editors say that this claim cannot be supported. Arguments can be made that other languages, like Indonesian/Malay or Finnish, may have as many or more Words than English

Appendix:

Hungarian, can also easily be the answer, with more than one MILLION distinct Words, of which 100.000+ are used in DAILY conversation today and ALL of the rest can be understood by today's erudite speakers.

Hungarian is a very old and unique language, with no language family relatiOShips (sorry uralic languages, bye-bye) and more than 30% of the Words being untraceable into any other language and more than 20% untranslatable.