As woman was formerly known in topless joint (3)
I believe the answer is:
nee
'as woman was formerly known' is the definition.
I can't tell whether this defines the answer.
'topless joint' is the wordplay.
'topless' means to remove the first letter.
'joint' becomes 'knee' (knee joint is a kind of joint).
'knee' with its first letter removed is 'NEE'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for nee that I've seen before include "Prefix denoting woman's name before marriage" , "Prefix to married woman's maiden name" , "Prefix indicating maiden name before marriage" , "Used to indicate the maiden name of a married woman" , "Adjective meaning born, followed by maiden name" .)