n. & v.
n. a derisive smile or remark.
v. 1 intr. (often foll. by at) smile derisively. 2 tr. say sneeringly. 3 intr. (often foll. by at) speak derisively esp. covertly or ironically (sneered at his attempts). sneerer n. sneeringly adv.
[ 16th c.: orig. unkn. ]