Expelled one female in group (8)
I believe the answer is:
banished
'expelled' is the definition.
(banishing is a kind of expelling)
'one female in group' is the wordplay.
'one' becomes 'i' (Roman numeral).
'female' becomes 'she' ('she' refers to a woman).
'in' means one lot of letters goes inside another.
'group' becomes 'band' (band can mean a group of people).
'i'+'she'='ishe'
'ishe' going into 'band' is 'BANISHED'.
(Other definitions for banished that I've seen before include "Condemned to exile" , "excluded?" , "Sent into exile" , "Exiled" .)