Dopamine is a neurotransmitter, and dopaminergic means "related to dopamine". Dopamine plays a number of roles in our bodies, including the "pleasure reward" function.
This is why dopaminergic is a good word to know. It's a word that can mean "related to a body's pleasure reward function".
For example, one can have a dopminergic response to something:
"Whenever I think about chocolate cake I have a dopaminergic response!"
"The dopaminergic antagonism of coffee caused me to stop drinking it last year."