misbelieving1
/ˌmɪsbɪˈliːvɪŋ/noun
The refusal or inability to accept something as true; misbelief; an instance of this.
Origin
Middle English; earliest use found in Ayenbite of Inwyt. From misbelieve + -ing.
misbelieving2
/ˌmɪsbɪˈliːvɪŋ/Now rare
adjective
1Holding a false belief; heretical, unorthodox.
2Not believing; sceptical; = disbelieving adjective. Now rare.
Origin
Middle English; earliest use found in Arthour and Merlin. From misbelieve + -ing.