Elderly, crotchety old men who think the world owes them favors because they are veterans. They will usually ask for special discounts, expect special favors and walk around like they are better than younger veterans because they served in the "real wars". Spev is short for "Special Veterans" and is likened to the derogatory term sped for "special ed". Note that not all veterans act like this and therefore not all veterans should be referred to as this.
Those crotchety old spevs were in again today whining about how we don't offer veteran discounts.