Hello Tom, there are a couple different ways to interpret this into ASL depending on the context. If what your character means is "I have not heard of this person before" then I would sign something like "Name me late know" or even just "late know me" as this indicates the person has not yet heard of that person. If what you mean is "that is a very strange name; I have never heard of someone being named that before" (like say the name given is Bealgathorp or something) then yes, I would sign "Name unique" or "name odd" (Odd is a sign I see more commonly than weird. Odd is the one where the C handshape of the dominant hand falls forward from the wrist when the hand is near the mouth). Hope that helps!