Flexible secretary lawyer's taken over desk (9)
I believe the answer is:
adaptable
'flexible' is the definition.
(similar in meaning)
'secretary lawyer's taken over desk' is the wordplay.
'secretary' becomes 'PA' (abbreviation for personal assistant).
'lawyer' becomes 'da' (abbreviation for District Attorney).
'taken over' shows that the letters should be reversed in order.
'desk' becomes 'table' (a desk is a table for working at).
'pa'+'da'='pada'
'pada' backwards is 'adap'.
'adap'+'table'='ADAPTABLE'
(Other definitions for adaptable that I've seen before include "having different uses?" , "Happy to fit in" , "Good at fitting in to new circumstances" , "Versatile" , "Able to be modified" .)