bu'a'a UI1b experimental cmavo

naturalistic interjection: used to express a fit of overwhelming or uncontrollable laughter; the stereotypical 'evil laugh'

Additional -'a syllables may be added as desired. See u'i, le'o, xa'a, cmila, palci

In notes:

x1 is an evil counterpart to x2 by moral standard x3, in contrast to x2 having property x4.
naturalistic interjection: laughter