Complex woman drops ecstasy into claret when sloshed (7)
I believe the answer is:
electra
'complex woman' is the definition.
(woman after whom the Electra Complex is named)
'drops ecstasy into claret when sloshed' is the wordplay.
'drops' suggests taking the first letters (I've seen 'drop of' mean this).
'into' means one lot of letters goes inside another.
'when sloshed' is an anagram indicator.
The initial letter of 'ecstasy' is 'e'.
'claret' is an anagram of 'elctra'.
'e' placed within 'elctra' is 'ELECTRA'.
(Other definitions for electra that I've seen before include "Agamemnon's child" , "Mythical woman with a complex?" , "Daughter of Agamemnon and Clytemnestra (who has a complex?)" , "Greek heroine (with a complex!)" , "heroine of Greece" .)