He swore it moved differently (9)
I believe the answer is:
otherwise
'differently' is the definition.
(I know that differently can be written as otherwise)
'he swore it moved' is the wordplay.
'moved' indicates an anagram.
'he'+'swore'+'it'='hesworeit'
'hesworeit' anagrammed gives 'OTHERWISE'.
(Other definitions for otherwise that I've seen before include "As an alternative - like white rose" , "White rose (anag.)" , "White rose seen in a different way" , "In other respects or ways" , "in different circumstances" .)