Form of discrimination is depressing male after time (6)
I believe the answer is:
ageism
'form of discrimination' is the definition.
(I've seen this before)
'is depressing male after time' is the wordplay.
'depressing male' becomes 'm' (common abbreviation. I am not sure about the 'depressing' bit.).
'after' means one lot of letters go next to another.
'time' becomes 'age' (an age is a period of time).
'is'+'m'='ism'
'ism' after 'age' is 'AGEISM'.
Can you help me to learn more?
(Other definitions for ageism that I've seen before include "Prejudice in relation to advanced years" , "Discrimination on grounds of age" , "Prejudice against senior citizens" , "discriminating against the elderly?" , "Prejudice on grounds of advanced years" .)