spank

n slap with a flat hand, esp on the buttocks 掴（尤指打屁股）: a spank on the bottom 打在屁股上的一巴掌.

spaceman, spaceship, spaceshuttle, spacesuit, spacewalk, spacing, spacious, spaciously, spaciousness, spackle, spade, spadeful, spadework, spaghetti, Spain, spam, span, spangle, spaniel, Spanish, spanking, spanner, spar, spare, spare part, spare tyre, spare-rib, spare...from, sparing, sparingly, spark, sparking-plug (also `spark-plug), sparkle, sparkler, sparkling, sparks, sparring-partner, sparrow, sparrow-hawk, sparse,