Fish emitted unpleasant odour (5)
I believe the answer is:
smelt
'fish' is the definition.
(I know that smelt is a type of fish)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for smelt that I've seen before include "Food fish often fried" , "were high" , "Stank" , "humming" , "Small silvery fish" .)