Wife is American beauty (6)
I believe the answer is:
missus
'wife' is the definition.
(someone's missus is their wife)
'is american beauty' is the wordplay.
I cannot really see how this works, but
'is' is within the answer.
'american' could be 'us' (United States) and 'us' is present in the answer.
The remaining letters 'ms' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for missus that I've seen before include "Wife (informal)" , "Wife (colloquial)" , "trouble and strife" , "Dutch American" , "The old lady" .)