Deepest point in drain perhaps (5)
I believe the answer is:
nadir
'deepest point' is the definition.
(I've seen this before)
'drain perhaps' is the wordplay.
'perhaps' indicates anagramming the letters.
'drain' with letters rearranged gives 'NADIR'.
'in' acts as a link.
(Other definitions for nadir that I've seen before include "businessman formerly escaping justice" , "Drain into the lowest point (5)" , "Low-water mark" , "Low point" , "Rock bottom" .)