chapuzón
plunge
chap-
splash
+
-ón
augmentative suffix
Chapuzón means plunge and can be thought of as a big splash1 (-ón1) combined with the idea of splashing0 (chap-0).
noun
- plungeA quick dip or plunge into waterNos dimos un chapuzón en el lago para refrescarnos. // We took a plunge in the lake to cool off.