dis ‧ a ‧ buse /ˌdɪsəˈbjuːz/ BrE AmE verb [transitive] formal
[ Date: 1600-1700 ; Origin: dis- + ⇨ ↑ abuse 2 'to deceive' (15-18 centuries) ]
to persuade someone that what they believe is not true
disabuse somebody of something
I tried to disabuse him of that notion.