small horned rattlesnake of southwestern U.S., 1875, American English, from side (adj.) + agent noun of wind (v.), so called in reference to its "peculiar lateral progressive motion." Also sidewiper (1888).
"excellent thing" (especially a rousing speech), 1892, from stem-winding watches (1875), which were advanced and desirable when introduced. See stem (n.) + wind (v.1).
