During meeting, start to employ one's discrimination (6)
I believe the answer is:
ageism
'discrimination' is the definition.
(ageism is a kind of discrimination)
'during meeting start to employ one's' is the wordplay.
'during' indicates putting letters inside.
'meeting' becomes 'agm' (I can't explain this - if you can you should believe this answer much more).
'start to' says to take the initial letters.
'one's' becomes 'is' (Roman numeral).
The first letter of 'employ' is 'e'.
'e'+'is'='eis'
'agm' enclosing 'eis' is 'AGEISM'.
Can you help me to learn more?
(Other definitions for ageism that I've seen before include "Prejudice on grounds of advanced years" , "Prejudice in relation to advanced years" , "Discrimination e.g. against old people" , "Discrimination on grounds of age" , "Prejudice or bias against old people" .)