'Big Brother' Luke Valentine's Father Says Son Isn't Racist, Has Black Family

The "Big Brother" houseguest who got tossed, because he used the n-word, is NOT a racist ... according to his father, who says their family ties prove a lack of prejudice.

If ya missed it, Luke Valentine was booted this week after live feeds captured him using the racial slur in conversation with 2 other white houseguests, as well as a Black man. His dad, James, tells us his son's behavior was surprising and disappointing for a few reasons.

Luke's father says his son has many family members who are Black, including a stepmom and step-siblings, as well as biracial cousins ... and he says Luke is absolutely not a racist and was not raised in a racist family.

The dad says Luke's stepmother was also disappointed to hear him use the n-word on the live feeds, but we're told she feels he's a good kid regardless and they have a good relationship.

Luke's pops also says he's never heard Luke using the racial slur, and he believes his son was not intending to be racist, though he admits his kid said the wrong thing and has to be more mindful of what comes out of his mouth.

Needless to say, Thanksgiving's gonna be interesting.

TMZ broke the story ... CBS kicked Luke off the show the same day as the incident, telling us there's "zero tolerance in the house for using a racial slur."

James says it's disappointing his son was kicked off the show, in part because he seemed to be enjoying himself, and the family wanted to see him on the program longer.