The uncleared part of the forest? (4)
I believe the answer is:
rest
'the uncleared part' is the definition.
'rest' can be an answer for 'part' (rest is a kind of part). I am unsure of the 'the uncleared' bit.
'the forest?' is the wordplay.
'REST' is hidden in amongst the letters.
But, I am uncertain how the hidden word is indicated.
'of' is the link.
Can you help me to learn more?
(Other definitions for rest that I've seen before include "Take one's ease" , "'Relax, pause from work (4)'" , "Repose - remainder" , "Repose, others" , "Stay" .)