Second person reported a tree (3)
I believe the answer is:
Here is my best explanation:
'a tree' is the definition.
(yew is a kind of tree)
'second person reported' is the subsidiary indication.
'second person' becomes 'you' (I've seen this before).
'reported' shows a homophone (sound like).
'you' sounds like 'yew'.
(Other definitions for yew that I've seen before include "Tree with red berries", "Wood for archers", "Wood for bows", "Coniferous tree", "Conifer", "Churchyard tree", "'Evergreen tree, reddish-brown wood (3)'", "Evergreen tree with dark needles and red berries", "Evergreen tree with dark leaves and red berries" and "Tree associated with graveyards".)