Even at C2 level, you will still encounter new words every day, but the frequency drops dramatically from the hundreds of new items per day at B2 to just a handful, often fewer than five, in most reading or listening sessions. At the highest levels, the new vocabulary is almost always low-frequency, domain-specific terms, rare idioms, or highly literary language that even native speakers might not know. The shift is from learning core vocabulary to filling in the long tail of the language.
At B2, you are still building the bulk of everyday vocabulary and common phrasal verbs, which is why you see so many new items daily. At C2, you have already internalized the vast majority of words used in general conversation, news, and most professional contexts. New words now come from specialized fields like law, medicine, academic jargon, or from reading classic literature, poetry, or very niche hobbies. You might also encounter new phrasal verbs, but they tend to be less frequent and more idiomatic, like 'to rabbit on' or 'to faff about'.
The honest tradeoff is that progress at C2 feels much slower and less rewarding in terms of vocabulary growth. You will spend more time refining nuance, collocations, and register rather than acquiring many new words. To keep improving, you need to deliberately seek out challenging material: read academic papers in your field, listen to expert panel discussions, or read older literary works. A good next step is to keep a vocabulary journal of only the most interesting or useful new terms you find each week, and review them in context. You can also use spaced repetition systems with custom cards for these rare words, but be selective to avoid overload.
For concrete next steps, try reading one article from a high-level source like The Economist or a peer-reviewed journal in your target language each day, and note any unfamiliar terms. Use a dictionary that provides example sentences and collocations. Also, listen to unscripted interviews or debates on complex topics. Over time, you will notice that the number of new words per week shrinks to a steady trickle, which is a sign of true advanced proficiency. Remember that even native speakers encounter unknown words regularly, so this is a normal part of lifelong learning.