Sure it’s not* the* indicator of intellect or intelligence but I think it’s excessive to reduce to it merely to having the ability to open a thesaurus.
Many times I don’t get references to pop culture/history etc that people make. Does that make me less intelligent? No. But does that make the other person more knowledgeable? Yes. Is that a plus point he/she has over me? I think so.
Same goes for an extensive vocabulary that is used coherently and with proper grammar. You can’t do that with a thesaurus sitting in one day. It comes from a long term pattern of knowledge seeking (one example is reading, another is good education). And I would like to think that if you have two groups, one of “scholarly” people and one of a regular mix of people, then the former one will have a higher # of members who actively seek knowledge.
All I’m saying is give credit where it’s due but the answer to Nomi’s question, like almost everyone is saying, is: not necessarily.