Morning passable when out of control? (4)
I believe the answer is:
amok
'out of control?' is the definition.
(I've seen this in another clue)
'morning passable' is the wordplay.
'morning' becomes 'am'.
'passable' becomes 'ok'.
'am'+'ok'='AMOK'
'when' acts as a link.
(Other definitions for amok that I've seen before include "'Wildly, without self-control (4)'" , "Run thus to run wildly about" , "Uncontrolled or murderous way to run!" , "Frenzied, running out of control" , "Berserk" .)