Meaning

noun a vigorous blow

noun a serious collision (especially of motor vehicles)

noun a hard return hitting the tennis ball above your head

originUncertain, probably of onomatopoeic origin. Compare Swedish smask (“to smack with the lips”), dialectal Swedish smaska (“to smack, kiss”), Danish smaske (“to smack with the lips”), Low German smaksen (“to smack with the lips, kiss”).

Etymology from Wiktionary, CC BY-SA 3.0