Khloe Kardashian Flashes Engagement Ring While Watching Tristan Thomspon Courtside

Khloe Kardashian watched attentively Saturday night as BF Tristan Thompson tried in vain to beat the L.A. Clippers ... and she did nothing to stop the rumor she's engaged.

Khloe was wearing a massive ring as she sat with pal Malika Haqq. She's worn the ring over the last few days, but mum's been the word.

Khloe officially got divorced from Lamar Odom in December.