That woman? Alien in charge of contrary beliefs! (7)
I believe the answer is:
heretic
'of contrary beliefs' is the definition.
The definition suggests a singular noun which matches the answer.
'that woman? alien in charge' is the wordplay.
'that woman?' becomes 'her' ('her' refers to a woman).
'alien' becomes 'et' (extra terrestrial).
'in charge' becomes 'ic' (abbreviation for 'in charge').
'her'+'et'+'ic'='HERETIC'
Can you help me to learn more?
(Other definitions for heretic that I've seen before include "Misbeliever" , "contrarian" , "person not acting in good faith?" , "Person with views contrary to accepted beliefs" , "Nonconformist" .)