To help out a raw beginner is uninteresting (4)
I believe the answer is:
arid
'uninteresting' is the definition.
(I've seen this in another clue)
'to help out a raw beginner' is the wordplay.
'to help' becomes 'aid' (synonyms).
'out' means one lot of letters goes inside another.
'beginner' says to take the initial letters.
The initial letter of 'raw' is 'r'.
'aid' enclosing 'r' is 'ARID'.
'is' acts as a link.
(Other definitions for arid that I've seen before include "Dry and withered" , "Very dry, having little rain" , "Parched and barren" , "(Of climate) dry" , "Without much rainfall" .)