Beaming princess almost taken in by traitor (7)
I believe the answer is:
radiant
'beaming' is the definition.
(I know that beaming can be written as radiant)
'princess almost taken in by traitor' is the wordplay.
'princess' becomes 'diana' (I have seen 'British princess' mean 'diana' so perhaps 'princess' could also mean 'diana').
'almost' means to remove the last letter (most of the word but not all of it).
'taken in' is an insertion indicator.
'by traitor' becomes 'rat' (rat can mean a traitor. I am not sure about the 'by' bit.).
'diana' with its final letter removed is 'dian'.
'dian' going into 'rat' is 'RADIANT'.
Can you help me to learn more?
(Other definitions for radiant that I've seen before include "Shining - happy" , "Straight line" , "Brilliant" , "Luminous" , "beaming with joy" .)