Is nothing after the usual time put into quarantine? (7)
I believe the answer is:
isolate
'put into quarantine?' is the definition.
(I've seen this before)
'is nothing after the usual time' is the wordplay.
'nothing' becomes 'o' (looks like zero - 0).
'after the usual time' becomes 'late' (I've seen this before).
'is'+'o'+'late'='ISOLATE'
(Other definitions for isolate that I've seen before include "Segregate or quarantine" , "Strand" , "Ostracise" , "Put into quarantine" , "put away?" .)