Tavreynya
You can write characters who are smarter than you very easily, by having them spout a lot of really long words. It's best if you have no idea what they're saying. Because there isn't the slightest chance that any of your readership will know
any of those words, honest to Bob.
Scientific words are best. In fact, your character should never refer to anything so simply such as a "daisy" and the like; they should always refer to it as "Chrysanthemum leucanthemum" instead, and ditto for the rest. And, no, this will never get odd looks, for we all know that smart people (even just moderately smart people) do this constantly. And, since scientific names are so confusing (and research, as we all know it, is
so last week), how about just making those words up instead? It's so much quicker, and, really, no one will ever notice or think something's up, not even in the slightest.