Einstein’s decade? (7,8)

'einstein's decade?' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.

'einstein's decade?' is the wordplay.
'einstein's' becomes 'naughty' (I can't justify this - if you can you should give a lot more credence to this answer).
'decade?' becomes 'nineties' (nineties is a kind of decade).
'naughty'+'nineties'='NAUGHTY NINETIES'