Internet threat, item remaining to be picked up before start of year (6)
I believe the answer is:
trojan
'year' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for trojan that I've seen before include "Paris, for example - harmful computer program" , "This horse was a wooden decoy" , "Paris for one" , "Hard grafter (from an ancient city?)" , "Horse filled with Greek soldiers" .)