Drives at happy mediums (5)
I believe the answer is:
means
This clue might be a double definition.
'drives' is the first definition.
The answer and definition can be both to do with communicating as well as being verbs in their -s form.
Perhaps you can see an association between them that I don't see?
'happy mediums' is the second definition.
Although both the answer and definition are plural nouns, I can't see how one could define the other.
'at' acts as a link.
Can you help me to learn more?
(Other definitions for means that I've seen before include "Pecuniary resources" , "Intends - capital" , "has significance" , "Signifies" , "considerable income" .)