Trick is not commonly behind straight embarrassment (10)
I believe the answer is:
constraint
'embarrassment' is the definition.
(thesaurus)
'trick is not commonly behind straight' is the wordplay.
'trick' becomes 'con' (a con is a fraud or trick).
'is not commonly behind straight' becomes 'straint' (I can't explain this - if you can you should believe this answer much more).
'con'+'straint'='CONSTRAINT'
Can you help me to learn more?
(Other definitions for constraint that I've seen before include "confinement" , "Limit - restriction" , "force" , "restriction made" , "Check" .)