When you disapprove of someone, you disfavor them. The wicked stepmother in "Cinderella" favored her own daughters but disfavored poor Cinderella. Thank goodness for that glass slipper.
You probably know your parents well enough that it's perfectly obvious when you've fallen into their disfavor. This probably only means they're annoyed or angry at you, although in some cases disfavor can mean true dislike. You can also use this word as a verb: "The political system disfavors people who don't have much money."