16 down
Doctor:
send
Clara
for
lists
of
appointments
(9)
Doctor: send Clara for lists of appointments (9)
hints
0
checks
0
hints
The definition is at the end of the clue.
How the clue works
The definition's at the end there — lists of appointments is exactly what calendars are. "Doctor" is your anagram signal, telling you to mangle the letters of "send Clara" into a new shape, and sure enough they rearrange perfectly into CALENDARS.