Time, perhaps, Hamlet returned? So it is (6)
I believe the answer is:
tragic
'so it is' is the definition.
I can't tell whether this definition defines the answer.
'time perhaps hamlet returned?' is the wordplay.
'time' becomes 't' (abbreviation).
'perhaps hamlet' becomes 'cigar' (brand of cigar).
'returned?' is a reversal indicator (I've seen 'return' mean this).
'cigar' reversed gives 'ragic'.
't'+'ragic'='TRAGIC'
(Other definitions for tragic that I've seen before include "like King Lear" , "Disastrous, appalling" , "Grievous" , "Terrible" , "Pathetic" .)