Bobby Brown -- I'm PISSED About My Daughter's Engagement

TMZ Photog: "How excited are you for your daughter -- she's about to get married and stuff?"
Bobby Brown: "I'M NOT."

That basically sums up Bobby B's feeling about his daughter Bobbi Kristina getting engaged to Nick "He's Not My Biological Brother" Gordon.

Bobby made it clear he doesn't approve ... and reveals that Nick never even called him up to ask for her hand in marriage.

The Brown family isn't exactly the tightest bunch -- Bobbi Kristina doesn't talk to her dad, so why would Nick?

Still let's recap ... the not-official brother didn't call his quasi step-dad to ask permission to marry his kinda-sister.

Despite the bitterness, Bobby tells TMZ ... "I just want her to be happy."

We broke the story, Bobbi K revealed the engagement on Facebook last week ... and though Whitney treated Nick like a son growing up, he's not a blood relative and was never formally adopted.