3 "not hard" for Rowan? (4)
I believe the answer is:
tree
'rowan?' is the definition.
(rowan is a kind of tree)
'3 not hard' is the wordplay.
'3' becomes 'three' (synonyms).
'not' indicates named letters should be taken away.
'hard' becomes 'h' (abbreviation used in pencil classifications).
'three' with 'h' taken out is 'TREE'.
'for' acts as a link.
(Other definitions for tree that I've seen before include "Source of wood" , "Holly, perhaps" , "Root-and-branch plant?" , "Beech, for example" , "Shoe stretcher" .)