[ 'sʌməsɒlt , -sɔ:lt ]
■ noun
1》 an acrobatic movement in which a person turns head over heels in the air or on the ground and finishes on their feet.
2》 a dramatic upset or reversal of policy or opinion.
■ verb perform a ~.
Origin
C16 (asnoun): from OFr. sombresault , from Provençal sobresaut , from sobre 'above' + saut 'leap'.