1. causing harm or damage
the detrimental impact of something
'Detrimental' is an adjective describing something dangerous or which threatens to cause harm. Something might be detrimental if it might cause an accident in the future, such as a 'detrimental problem with the road'. It can also be used to talk about psychological or health effects 'a detrimental effect on health'. 'Constant criticism is detrimental to a child's wellbeing.' This is an adjective that is used more often in formal situations.