Derides old Fujitsu leader twice with glass shattered (5,3)

'derides' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.

'old fujitsu leader twice with glass shattered' is the wordplay.
'old' becomes 'o' (abbreviation).
'leader' suggests taking the first letters.
'twice' indicates the doubling of some letters.
'with' says to put letters next to each other.
'shattered' indicates anagramming the letters.
The initial letter of 'fujitsu' is 'f'.
'f' doubled is 'ff'.
'glass' with letters rearranged gives 'slags'.
'o'+'ff'='off'
'off' put after 'slags' is 'SLAGS OFF'.

Can you help me to learn more?