This is the 449th most frequent Hungarian word.
mindenkit
"Everyone" or "everybody."
Here, 'mindenkit' is again the accusative form and serves as the object of the verb 'megértem' (I understand). It is used to express encompassing understanding toward all individuals cited in the relative clause.
Megértem mindenkit, aki szomorú.
I understand everyone who is sad.
'Mindenkit' in this usage serves also in the accusative case, but in this imperative-conjoined expression, it emphasizes the indirect action directed towards the universal group referred to.
Mondj el mindent mindenkit érdekelni fog!
Say everything; everyone will be interested!
In this sentence, 'mindenkit' is the accusative form of 'mindenki', meaning it is used as the direct object of the verb 'meghívtunk' (we invited). It translates to 'everyone' in the context of addressing all individuals inclusively.