One girl sadly without sex appeal hanging around for client? (9)
I believe the answer is:
loitering
'hanging around for client?' is the definition.
(as in soliciting)
'one girl sadly without sex appeal' is the wordplay.
'sadly' indicates an anagram.
'without' means one lot of letters goes inside another ('without' can be similar in meaning to 'outside').
'sex appeal' becomes 'it'.
'one'+'girl'='onegirl'
'onegirl' with letters rearranged gives 'loering'.
'loering' placed around 'it' is 'LOITERING'.
(Other definitions for loitering that I've seen before include "Hanging around or lurking" , "Lingering" .)