i think u wrote the wrong word bro, perjudicil doesnt exist i reckon, and going to the previous word, perjudicial, it's an adjective, when sth is perjudicial it might hurt u, or cause u troubles, in most of the cases, we use this word when we refer to health. As an example, "El fumar es perjudicial para la salud" "estar mucho tiempo sentado puede ser perjudicial, "estar en frente de una computadora(ordenador in Spain) puede ser perjudicial para la vista".
Some other words with the same root would be, perjuicio (noun, sometimes it is used when it comes to law matters, "me han denunciado por daños y perjuicios", perjudicar(verb, when we hurt, or cause hassles to some1)
hope this helps. Greetings!