Gutless viking informer (4)
I believe the answer is:
nose
'informer' is the definition.
(I've seen this before)
'gutless viking' is the wordplay.
'gutless' says to hollow out the word (remove centre letters).
'viking' becomes 'norse' (I've seen this before).
'norse' with its centre removed is 'NOSE'.
(Other definitions for nose that I've seen before include "Organ of smell" , "Deserving blame" , "Don't cut this off to spite your face" , "See 7" , "Flair (for wine)" .)