Tree nearly everybody gets embarrassed about (5)
I believe the answer is:
alder
'tree nearly' is the definition.
'alder' can be an answer for 'tree' (I've seen this before). I'm not sure about the 'nearly' bit.
'everybody gets embarrassed about' is the wordplay.
'everybody' becomes 'al' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'gets' means one lot of letters go next to another.
'embarrassed' becomes 'red' (someone may blush or go red when embarrassed).
'about' is a reversal indicator.
'red' back-to-front is 'der'.
'al'+'der'='ALDER'
Can you help me to learn more?
(Other definitions for alder that I've seen before include "Tree akin to the birch" , "Tree or shrub of the birch family" , "Catkin-bearing tree" , "Shrub or tree with cone-like fruits" , "Tree growing in damp ground" .)