Drain cracked in lowest point (5)
I believe the answer is:
nadir
'lowest point' is the definition.
(I've seen this before)
'drain cracked' is the wordplay.
'cracked' indicates an anagram.
'drain' is an anagram of 'NADIR'.
'in' acts as a link.
(Other definitions for nadir that I've seen before include "pits" , "Drain to lowest level" , "You can't sink lower!" , "Lowest point, or time of deepest depression." , "most unsuccessful point" .)