Even bits of Martha's elbow beaten black and blue (2,1,3,3)
I believe the answer is:
at a low ebb
'blue' is the definition.
(both can mean sad)
'even bits of martha's elbow beaten black' is the wordplay.
'even bits of' means one should take alternating letters.
'beaten' is an anagram indicator (letters beaten up or destroyed).
'black' becomes 'b' (as in pencil classifications).
The alternate letters of 'martha' are 'ata'.
'elbow' with letters rearranged gives 'loweb'.
'ata'+'loweb'+'b'='AT A LOW EBB'
'and' acts as a link.
(Other definitions for at a low ebb that I've seen before include "Lacking vigour" , "in ailing state" , "when the beach is empty" , "In recession" , "In a weak state" .)