23 down
Greek
character
turning
up
at
what
time?
(5)
Greek character turning up at what time? (5)
hints
0
checks
0
hints
The definition is at the beginning of the clue.
How the clue works
Greek character gives us a Greek letter. 'Turning up' signals a reversal in a down clue, so we flip the charade AT ('at') plus EH (an exclamation meaning 'what?') plus T (short for 'time'), and the whole lot reversed spells out our answer.