Please see the full writeup for the southern colloqialism:

Shit Out of Luck

S.O.L. is both the written and verbal abbreviation of this conversational spice. Pronounced phonecically "Ess Oh Ell." Why is the "of" so conspicuously missing? Two reasons.

1. It's a preposition, thus it's SOP to drop it from an acronym, even a colloquial one.

2. "SOOL", rhyming with "fool," sounds stupid.

USAGE

At the Fridge: Look, I just got the last beer. Looks like you're SOL, my friend.