A brisant explosive is one in which the maximum pressure is attained so rapidly that a shock wave is formed, and the net effect is to shatter material surrounding or in contact with it. Thus brisance is a measure of the shattering ability of an explosive.
This characteristic is of practical importance in determining the effectiveness of an explosion in fragmenting shells, bomb casings, grenades, and the like.
One of the most brisant conventional explosives is Cyclotrimethylene trinitramine.
Initial version taken from U.S. Military public domain resource at https://www.advancement.cnet.navy.mil/products/web-pdf/tramans/bookchunks/14324_ch1.pdf