Broken-up female thinking about practical joke (10)

'broken-up' is the definition.
(broken into fragments)

'female thinking about practical joke' is the wordplay.
'female' becomes 'f' (abbreviation).
'thinking' becomes 'mental' (relating to the mind).
'about' means one lot of letters go next to another.
'practical joke' becomes 'rag' (rag is a kind of practical joke).
'mental' put after 'rag' is 'ragmental'.
'f'+'ragmental'='FRAGMENTAL'