She sues three committee members and an ordinary worker (11)
I believe the answer is:
complainant
'she sues three committee' is the definition.
I can't judge whether this definition defines the answer.
'members and an ordinary worker' is the wordplay.
'members' becomes 'com' (I can't explain this - if you can you should give a lot more credence to this answer).
'and' is a charade indicator (letters next to each other).
'an ordinary' becomes 'plain' (I've seen this in other clues).
'worker' becomes 'ant' (worker is a type of ant).
'com'+'plain'+'ant'='COMPLAINANT'
Can you help me to learn more?
(Another definition for complainant that I've seen is " One bringing an action".)