Meaning
"to laugh," is found in Luk 6:21, Luk 6:25. This signifies loud laughter in contrast to demonstrative weeping.
<2,,2606, katagelao>
denotes "to laugh scornfully at," more emphatic than No. 1 (kata, "down," used intensively, and No. 1), and signifies derisive laughter, Mat 9:24, Mar 5:40, Luk 8:53. Cp. ekmukterizo, "to deride."
Note: The laughter of incredulity, as in Gen 17:17, Gen 18:12, is not mentioned in the NT.