The order of the senses are normally based on frequency and convenience.
However in this case, the meanings apart from the first (undead) sense of the word are colloquial, and as such not used in formal (explicit) discourse.
Therefore it is acceptable to conveniently decide to call a dull or apathetic person a 'zombie' in casual circumstances, but you are in fact appealing to its 'zombie-
like' traits and these are of course subjective.
My workmates are 'zombies', in the same sense.
If you think this discussion is overly analytical nitpicking, why are you indulging in it?
:cool: