Know-it-all as a noun is someone who acts as if he/she knows everything and believes him/herself above others as a result, normally intended as a pejorative. while Know-all as a noun is someone who obnoxiously claims to be knowledgeable on a subject.
Part of speech: noun
Definition: Someone who acts as if he/she knows everything and believes him/herself above others as a result, normally intended as a pejorative.
Part of speech: noun
Definition: Someone who obnoxiously claims to be knowledgeable on a subject.
We hope you now know whether to use Know-it-all or Know-all in your sentence.