ex-pertness (noun) expertness: ability
Sinonime: break up,
burst*, cachinnate, chortle, chuckle, convulsed, crack up, crow, die laughing, fracture, giggle,
grin, guffaw, howl, roar, roll in the aisles,
scream, shriek, snicker, snort, split one's sides, titter, whoop, with sound be in stitches
Antonime: cry