Yes, LOINS is a Scrabble word!

Letter values in Scrabble US: L 1, O 1, I 1, N 1, S 1.

Is it a valid word?

LOINS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

the lower part of the abdomen just above the external genital organs
the region of the hips and groin and lower abdomen
a cut of meat taken from the side and back of an animal between the ribs and the rump
either side of the backbone between the hipbone and the ribs in humans as well as quadrupeds

Also: pubic region.

Not playable in Scrabble US: LUMBUS.