Discrimination when contents of package is mislabelled (6)
I believe the answer is:
ageism
'discrimination' is the definition.
(I know that ageism is a type of discrimination)
'contents of package is mislabelled' is the wordplay.
'contents of' indicates a hidden word.
'AGEISM' is hidden within 'package is mislabelled'.
'when' is the link.
(Other definitions for ageism that I've seen before include "Prejudice against older people" , "Prejudice in relation to advanced years" , "Discrimination against the elderly" , "Form of discrimination" , "Prejudice against senior citizens" .)