Deduce knight consumed by raging fire (5)
I believe the answer is:
infer
'deduce' is the definition.
(synonyms)
'knight consumed by raging fire' is the wordplay.
'knight' becomes 'N' (chess abbreviation).
'consumed by' is an insertion indicator (inserted letters get consumed).
'raging' indicates anagramming the letters.
'fire' with letters rearranged gives 'ifer'.
'n' inserted inside 'ifer' is 'INFER'.
(Other definitions for infer that I've seen before include "Deduce, surmise" , "Establish by deduction" , "Deduce logically" , "Extrapolate, conclude" , "Presume" .)