Mistaken for a monster, outspoken scientist drops initial interest (12)
I believe the answer is:
frankenstein
'mistaken for a monster' is the definition.
(Frankenstein refers to the monster's creator)
'outspoken scientist drops initial interest' is the wordplay.
I cannot quite see how this works, but
'outspoken' could be 'frank' (synonyms) and 'frank' is present in the answer.
This explanation may well be incorrect...
(Other definitions for frankenstein that I've seen before include "Monster's creator" , "Monster inventor" , "that could ruin manufacturer" , "Mary Shelley's monster-making baron" , "Monstrous and dangerous humanoid" .)