Liverpudlian songstress not well in California (5)
I believe the answer is:
cilla
'liverpudlian songstress' is the definition.
I don't know anything about this answer so I cannot judge whether this works.
'not well in california' is the wordplay.
'not well' becomes 'ill' ('ill' is the opposite to 'well').
'in' means one lot of letters goes inside another.
'california' becomes 'ca'.
'ill' going into 'ca' is 'CILLA'.
Can you help me to learn more?
(Other definitions for cilla that I've seen before include "- Black, TV personality and singer" , "Colourful old singer" .)