Be a shade embarrassed? (6)
I believe the answer is:
redden
'be' is the definition.
Although both the answer and definition are verbs in their base form, I don't see how one could define the other.
'a shade embarrassed?' is the wordplay.
'a shade' becomes 'red' (red is a colour or shade).
'embarrassed?' becomes 'den' (I can't justify this - if you can you should give a lot more credence to this answer).
'red'+'den'='REDDEN'
Can you help me to learn more?
(Other definitions for redden that I've seen before include "Give visible sign of embarrassment" , "Blush, colour accordingly" , "Group of states under one head" , "Evaluate the nature of (something)" , "Blush or become flushed" .)